TLSV1_ALERT_UNRECOGNIZED_NAME with connection to Keenetic SSTP fails

[QuAzI]

I am trying to use Keenetic SSTP. With Windows client it works fine, but with Open-SSTP-Client it always fails with

[2025-05-11 14:22:12.584] Establish VPN connection
[2025-05-11 14:22:12.778] OSC: ERR_UNEXPECTED
javax.net.ssl.SSLHandshakeException: Read error: ssl=0x74e3022148: Failure in SSL library, usually a protocol error
error:10000458:SSL routines:OPENSSL_internal:TLSV1_ALERT_UNRECOGNIZED_NAME (external/boringssl/src/ssl/tls_record.cc:594 0x74e3034e08:0x00000001)
	at com.android.org.conscrypt.SSLUtils.toSSLHandshakeException(SSLUtils.java:363)
	at com.android.org.conscrypt.ConscryptEngine.convertException(ConscryptEngine.java:1134)
	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:919)
	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:747)
	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:712)
	at com.android.org.conscrypt.Java8EngineWrapper.unwrap(Java8EngineWrapper.java:237)
	at kittoku.osc.terminal.SSLTerminal.receive$app_release(SSLTerminal.kt:407)
	at kittoku.osc.terminal.SSLTerminal.startSSLHandshake(SSLTerminal.kt:221)
	at kittoku.osc.terminal.SSLTerminal.access$startSSLHandshake(SSLTerminal.kt:62)
	at kittoku.osc.terminal.SSLTerminal$startSSLHandshake$1.invokeSuspend(Unknown Source:14)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at kotlinx.coroutines.internal.LimitedDispatcher.run(LimitedDispatcher.kt:42)
	at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:95)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:570)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:750)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:677)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:664)
Caused by: javax.net.ssl.SSLProtocolException: Read error: ssl=0x74e3022148: Failure in SSL library, usually a protocol error
error:10000458:SSL routines:OPENSSL_internal:TLSV1_ALERT_UNRECOGNIZED_NAME (external/boringssl/src/ssl/tls_record.cc:594 0x74e3034e08:0x00000001)
	at com.android.org.conscrypt.NativeCrypto.ENGINE_SSL_force_read(Native Method)
	at com.android.org.conscrypt.NativeSsl.forceRead(NativeSsl.java:589)
	at com.android.org.conscrypt.ConscryptEngine.unwrap(ConscryptEngine.java:911)
	... 15 more

[2025-05-11 14:22:12.787] Terminate VPN connection