I need to enable the TLS 1.2 on devices before 5.0 version. I implemented the TLSSocketFactory: TlSSocketFactory implementation and I implemented the AndroidCustomClientHandler AndroidCustomClientHandler My request to the server is: _client . SendAsync ( aRequest , cancellationToken . Token ); the aRequest is type of HttpRequestMessage. i receive an exception: Javax . Net . Ssl . SSLHandshakeException : java . security . cert . CertPathValidatorException : Trust anchor for ` . certification path not found. --->` Java . Security . Cert . CertificateException : java . security . cert . CertPathValidatorException : Trust anchor for certification path not found . ---> Java . Security . Cert . CertPathValidatorException : Trust anchor for certification path not found . --- End of inner exception stack trace --- --- End of inner exception stack trace --- at System . Runtime . ExceptionServices . ExceptionDispatchInfo . Throw () [ 0x0000c ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at Java . Interop . JniEnvironment + InstanceMethods . CallVoidMethod ( Java . Interop . JniObjectReference instance , Java . Interop . JniMethodInfo method , Java . Interop . JniArgumentValue * args ) [ 0x00069 ] in < 7802aa64ad574c33adca332a3fa9706a >: 0 at Java . Interop . JniPeerMembers + JniInstanceMethods . InvokeAbstractVoidMethod ( System . String encodedMember , Java . Interop . IJavaPeerable self , Java . Interop . JniArgumentValue * parameters ) [ 0x00014 ] in < 7802aa64ad574c33adca332a3fa9706a >: 0 at Javax . Net . Ssl . HttpsURLConnectionInvoker . Connect () [ 0x00000 ] in / Users / builder / data / lanes / 5945 / dffc5912 / source / monodroid / external / xamarin - android / src / Mono . Android / obj / Release / android - 26 / mcw / Javax . Net . Ssl . HttpsURLConnection . cs : 417 at Xamarin . Android . Net . AndroidClientHandler +<> c__DisplayClass42_0 .< ConnectAsync > b__0 () [ 0x0005a ] in / Users / builder / data / lanes / 5945 / dffc5912 / source / monodroid / external / xamarin - android / src / Mono . Android / Xamarin . Android . Net / AndroidClientHandler . cs : 308 at System . Threading . Tasks . Task . InnerInvoke () [ 0x0000f ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at System . Threading . Tasks . Task . Execute () [ 0x00010 ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 --- End of stack trace from previous location where exception was thrown --- at System . Runtime . ExceptionServices . ExceptionDispatchInfo . Throw () [ 0x0000c ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at System . Runtime . CompilerServices . TaskAwaiter . ThrowForNonSuccess ( System . Threading . Tasks . Task task ) [ 0x0003e ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at System . Runtime . CompilerServices . TaskAwaiter . HandleNonSuccessAndDebuggerNotification ( System . Threading . Tasks . Task task ) [ 0x00028 ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at System . Runtime . CompilerServices . TaskAwaiter . ValidateEnd ( System . Threading . Tasks . Task task ) [ 0x00008 ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at System . Runtime . CompilerServices . ConfiguredTaskAwaitable + ConfiguredTaskAwaiter . GetResult () [ 0x00000 ] in <f32579baafc1404fa37ba3ec1abdc0bd> : 0 at Xamarin . Android . Net . AndroidClientHandler +< DoProcessRequest > d__44 . MoveNext () [ 0x000e4 ] in / Users / builder / data / lanes / 5945 / dffc5912 / source / monodroid / external / xamarin - android / src / Mono . Android / Xamarin . Android . Net / AndroidClientHandler . cs : 357 How can I solve the problem?? Many Thanks. ... View more