diff --git a/app/src/main/kotlin/com/tutpro/baresip/Config.kt b/app/src/main/kotlin/com/tutpro/baresip/Config.kt
index 77ee9e25..afbc2e1d 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/Config.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/Config.kt
@@ -61,9 +61,36 @@ object Config {
         if (sipVerifyServer != "")
             config = "${config}sip_verify_server $sipVerifyServer\n"
 
-        val sipCaFile = previousVariable("sip_cafile")
-        if (sipCaFile != "")
-            config = "${config}sip_cafile $sipCaFile\n"
+        val caBundlePath = "${BaresipService.filesPath}/ca_bundle.crt"
+        val caBundleFile = File(caBundlePath)
+        val caFilePath = "${BaresipService.filesPath}/ca_certs.crt"
+        val caFile = File(caFilePath)
+        if (caFile.exists())
+            caFile.copyTo(caBundleFile, true)
+        else
+            caBundleFile.writeBytes(byteArrayOf())
+        Log.d(TAG, "Size of caFile = ${caBundleFile.length()}")
+        val cacertsPath = "/system/etc/security/cacerts"
+        val cacertsDir = File(cacertsPath)
+        var caCount = 0
+        if (cacertsDir.exists()) {
+            cacertsDir.walk().forEach {
+                if (it.isFile) {
+                    caBundleFile.appendBytes(
+                        it.readBytes()
+                            .toString(Charsets.UTF_8)
+                            .substringBefore("Certificate:")
+                            .toByteArray(Charsets.UTF_8)
+                    )
+                    caCount++
+                }
+            }
+            Log.d(TAG, "Added $caCount ca certificates from $cacertsPath")
+        } else {
+            Log.w(TAG, "Directory $cacertsDir does not exist!")
+        }
+        Log.d(TAG, "Size of caBundleFile = ${caBundleFile.length()}")
+        config = "${config}sip_cafile $caBundlePath\n"
 
         val dynamicDns = previousVariable("dyn_dns")
         if (dynamicDns == "no") {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/ConfigActivity.kt b/app/src/main/kotlin/com/tutpro/baresip/ConfigActivity.kt
index 02e782b7..fd12fc32 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/ConfigActivity.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/ConfigActivity.kt
@@ -70,7 +70,6 @@ class ConfigActivity : AppCompatActivity() {
     private var oldDnsServers = ""
     private var oldCertificateFile = false
     private var oldVerifyServer = false
-    private var oldCAFile = false
     private var oldLogLevel = ""
     private var oldDisplayTheme = -1
     private var oldContactsMode = ""
@@ -313,8 +312,8 @@ class ConfigActivity : AppCompatActivity() {
         verifyServer.isChecked = oldVerifyServer
 
         caFile = binding.CAFile
-        oldCAFile = Config.variable("sip_cafile") != ""
-        caFile.isChecked = oldCAFile
+        val caCertsFile = File(BaresipService.filesPath + "/ca_certs.crt")
+        caFile.isChecked = caCertsFile.exists()
 
         val certificatesRequest =
             registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
@@ -324,11 +323,8 @@ class ConfigActivity : AppCompatActivity() {
                             val inputStream =
                                 applicationContext.contentResolver.openInputStream(uri)
                                         as FileInputStream
-                            val caCertsPath = BaresipService.filesPath + "/ca_certs.crt"
-                            File(caCertsPath).copyInputStreamToFile(inputStream)
+                            caCertsFile.copyInputStreamToFile(inputStream)
                             inputStream.close()
-                            Config.replaceVariable("sip_cafile", caCertsPath)
-                            save = true
                             restart = true
                         } catch (e: Error) {
                             Utils.alertView(
@@ -340,6 +336,8 @@ class ConfigActivity : AppCompatActivity() {
                     }
                 else
                     caFile.isChecked = false
+                if (!caFile.isChecked && caCertsFile.exists())
+                    caCertsFile.delete()
             }
 
         caFile.setOnCheckedChangeListener { _, isChecked ->
@@ -361,11 +359,8 @@ class ConfigActivity : AppCompatActivity() {
                                 )
                                 return@setOnCheckedChangeListener
                             }
-                            val caCertsPath = BaresipService.filesPath + "/ca_certs.crt"
-                            Utils.putFileContents(caCertsPath, content)
-                            Config.replaceVariable("sip_cafile", caCertsPath)
+                            caCertsFile.writeBytes(content)
                             caFile.isChecked = true
-                            save = true
                             restart = true
                         }
                         ActivityCompat.shouldShowRequestPermissionRationale(
@@ -389,8 +384,8 @@ class ConfigActivity : AppCompatActivity() {
                     Utils.selectInputFile(certificatesRequest)
                 }
             } else {
-                Config.removeVariable("sip_cafile")
-                save = true
+                if (caCertsFile.exists())
+                    caCertsFile.delete()
                 restart = true
             }
         }
@@ -613,13 +608,6 @@ class ConfigActivity : AppCompatActivity() {
                     save = true
                 }
 
-                if (verifyServer.isChecked && !caFile.isChecked) {
-                    Utils.alertView(this, getString(R.string.error),
-                            getString(R.string.verify_server_error))
-                    verifyServer.isChecked = false
-                    return false
-                }
-
                 if (oldVerifyServer != verifyServer.isChecked) {
                     Config.replaceVariable("sip_verify_server",
                             if (verifyServer.isChecked) "yes" else "no")
diff --git a/app/src/main/res/values-cs/strings.xml b/app/src/main/res/values-cs/strings.xml
index b5e475ae..7a54077b 100644
--- a/app/src/main/res/values-cs/strings.xml
+++ b/app/src/main/res/values-cs/strings.xml
@@ -107,7 +107,6 @@
     <string name="tls_ca_file">Soubor TLS CA</string>
     <string name="failed_to_set_dns_servers">Nepodařilo se nastavit servery DNS</string>
     <string name="verify_server">Ověřit certifikáty serveru</string>
-    <string name="verify_server_error">Certifikáty serveru nelze ověřit bez souboru certifikační autority TLS.</string>
     <string name="verify_server_help">Pokud je tato možnost zaškrtnuta, ověřuje baresip certifikáty TLS uživatelského agenta SIP a proxy serverů SIP, pokud se používá přenos TLS. Pokud je zaškrtnuto, musí být načten také soubor TLS CA.</string>
     <string name="dtmf_inband">Události v pásmu RTP</string>
     <string name="dtmf_info">Žádosti SIP INFO</string>
diff --git a/app/src/main/res/values-es/strings.xml b/app/src/main/res/values-es/strings.xml
index b618c2fb..786a9472 100644
--- a/app/src/main/res/values-es/strings.xml
+++ b/app/src/main/res/values-es/strings.xml
@@ -257,7 +257,6 @@
     <string name="aec_extended_filter">Filtro extendido AEC</string>
     <string name="audio">Audio</string>
     <string name="verify_server_help">Si se marca, baresip verifica los certificados TLS del Agente de Usuario SIP y de los Servidores Proxy SIP cuando se utiliza el transporte TLS. Si se marca, también se debe cargar el archivo TLS CA.</string>
-    <string name="verify_server_error">Los certificados del servidor no pueden ser verificados sin el archivo TLS CA.</string>
     <string name="verify_server">Verificar los certificados del servidor</string>
     <string name="transfer_request_to">Solicitud de transferencia de llamada a</string>
     <string name="missed_call_from">Llamada perdida de</string>
diff --git a/app/src/main/res/values-fi/strings.xml b/app/src/main/res/values-fi/strings.xml
index 66481540..dc4b0c76 100644
--- a/app/src/main/res/values-fi/strings.xml
+++ b/app/src/main/res/values-fi/strings.xml
@@ -344,18 +344,14 @@
         ladataan Download-kansiosta. Turvallisuusyistä tuhoa tiedosto heti lataamisen jälkeen.
     </string>
     <string name="verify_server">Tarkista palvelinten sertifikaatit</string>
-    <string name="verify_server_error">Palvelinten sertifikaatteja ei voi tarkistaa ilman TLS
-        CA-tiedostoa.
-    </string>
     <string name="verify_server_help">Jos merkitty, baresip tarkistaa SIP-palvelinten
-        sertifikaatit, kun TLS-tiedonsiirto on käytössä.  Tällöin myös TLS CA-tiedoston on oltava
-        ladattuna.
+        sertifikaatit, kun TLS-tiedonsiirto on käytössä.
     </string>
     <string name="tls_ca_file">TLS CA-tiedosto</string>
-    <string name="tls_ca_file_help">Jos merkitty, tiedosto joka sisältää
-        sertifikaattiauktoriteettien (CA) julkiset sertifikaatit, on joko jo ladattu tai tullaan
-        lataamaan. Android versioon 9 saakka tiedosto nimeltään \'ca_certs.crt\' ladataan
-        Download-kansiosta.
+    <string name="tls_ca_file_help">Jos merkitty, tiedosto on joko jo ladattu tai tullaan
+        lataamaan, joka sisältää sellaisten sertifikaattiauktoriteettien (CA) julkiset sertifikaatit,
+        jotka eivät sisälly Android-käyttöjärjestelmään. Android versioon 9 saakka tiedosto
+        nimeltään \'ca_certs.crt\' ladataan Download-kansiosta.
     </string>
     <string name="audio">Audio</string>
     <string name="audio_settings">Audio-asetukset</string>
diff --git a/app/src/main/res/values-pt-rBR/strings.xml b/app/src/main/res/values-pt-rBR/strings.xml
index 762b4e48..4ff4559c 100644
--- a/app/src/main/res/values-pt-rBR/strings.xml
+++ b/app/src/main/res/values-pt-rBR/strings.xml
@@ -240,7 +240,6 @@
     <string name="dark_theme">Tema Escuro</string>
     <string name="android_contact_help">Se for marcado, este contato será adicionado nos contatos do Android.</string>
     <string name="verify_server_help">Se estiver marcado, o baresip verifica os certificados TLS do SIP User Agent e o SIP Proxy Servers quando o transporte TLS for usado. Se estiver marcado, o arquivo TLS CA também deve ser carregado.</string>
-    <string name="verify_server_error">Os certificados do servidor não podem ser aferidos sem o arquivo CA TLS.</string>
     <string name="verify_server">Verifique os certificados do servidor</string>
     <string name="dtmf_info">Solicitações INFO SIP</string>
     <string name="dtmf_inband">Eventos na Banda RTP</string>
diff --git a/app/src/main/res/values-pt/strings.xml b/app/src/main/res/values-pt/strings.xml
index 484402ae..f420ae16 100644
--- a/app/src/main/res/values-pt/strings.xml
+++ b/app/src/main/res/values-pt/strings.xml
@@ -235,7 +235,6 @@
     <string name="dark_theme_help">Impor o uso do tema escuro no ecrã</string>
     <string name="dark_theme">Tema Escuro</string>
     <string name="verify_server_help">Se estiver marcado, o baresip verifica os certificados TLS do SIP User Agent e o SIP Proxy Servers quando o transporte TLS for usado. Se estiver marcado, o ficheiro TLS CA também deve ser carregado.</string>
-    <string name="verify_server_error">Os certificados do servidor não podem ser aferidos sem o ficheiro CA TLS.</string>
     <string name="verify_server">Verifique os certificados do servidor</string>
     <string name="transfer_request_to">Chamada de solicitação de transferência para</string>
     <string name="missed_call_from">Ligação perdida de</string>
diff --git a/app/src/main/res/values-ru/strings.xml b/app/src/main/res/values-ru/strings.xml
index 332afd9b..20e87e04 100644
--- a/app/src/main/res/values-ru/strings.xml
+++ b/app/src/main/res/values-ru/strings.xml
@@ -232,7 +232,6 @@
     <string name="about_title_plus">О baresip+</string>
     <string name="stun_server_uri">URI-адрес сервера STUN/TURN</string>
     <string name="dark_theme">Темная тема</string>
-    <string name="verify_server_error">Сертификаты сервера не могут быть проверены без файла TLS CA.</string>
     <string name="verify_server">Проверка сертификатов сервера</string>
     <string name="peer">Пир</string>
     <string name="direction">Направление</string>
diff --git a/app/src/main/res/values-sv/strings.xml b/app/src/main/res/values-sv/strings.xml
index 4f831fcc..7fb7ed24 100644
--- a/app/src/main/res/values-sv/strings.xml
+++ b/app/src/main/res/values-sv/strings.xml
@@ -172,7 +172,6 @@
     <string name="failed_to_load_module">Kunde inte ladda modul.</string>
     <string name="audio_modules_help">Ljudkodekar som tillhandahålls av de förkryssade modulerna är tillgängliga för konton.</string>
     <string name="tls_ca_file">TLS CA-fil</string>
-    <string name="verify_server_error">Servercertifikat kan inte verifieras utan TLS CA-fil.</string>
     <string name="verify_server">Verifiera servercertifikat</string>
     <string name="chat_with">Chatta med %1$s</string>
     <string name="chat">Chattmeddelanden</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 2600bab4..308085a5 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -324,15 +324,13 @@
         below, a file called \'cert.pem\' is loaded from Download folder. For security reasons,
         delete the file after loading.</string>
     <string name="verify_server">Verify Server Certificates</string>
-    <string name="verify_server_error">Server Certificates cannot be verified without
-        TLS CA file.</string>
     <string name="verify_server_help">If checked, baresip verifies TLS certificates of SIP User
-        Agent and SIP Proxy Servers when TLS transport is used.  If checked, also TLS CA File has
-        to be loaded.</string>
+        Agent and SIP Proxy Servers when TLS transport is used.</string>
     <string name="tls_ca_file">TLS CA File</string>
-    <string name="tls_ca_file_help">If checked, a file containing TLS certificates
-        of needed Certificate Authorities has been or will be loaded. In Android versions 9 and
-        below, a file called \'ca_certs.crt\' is loaded from Download folder.</string>
+    <string name="tls_ca_file_help">If checked, a file has been or will be loaded that contains
+        TLS certificates of such Certificate Authorities that are not included in Android OS.
+        In Android versions 9 and below, a file called \'ca_certs.crt\' is loaded from
+        Download folder.</string>
     <string name="audio">Audio</string>
     <string name="audio_settings">Audio Settings</string>
     <string name="audio_modules_title">Audio Modules</string>