java.security.cert.CertPathValidatorException: Trust anchor

{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 Java.Interop.JniEnvironment+InstanceMethods.CallVoidMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args) [0x00069] in <8acc8089c2ed40d08469fbaa6710a44c>:0

at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeAbstractVoidMethod (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x00014] in <8acc8089c2ed40d08469fbaa6710a44c>:0

at Javax.Net.Ssl.HttpsURLConnectionInvoker.Connect () [0x0000a] in <6f8818d6ffa14f4bad6fb5f5d0f0e665>:0

at Xamarin.Android.Net.AndroidClientHandler+<>c__DisplayClass43_0.b__0 () [0x0005a] in <6f8818d6ffa14f4bad6fb5f5d0f0e665>:0

at System.Threading.Tasks.Task.InnerInvoke () [0x0000f] in :0

at System.Threading.Tasks.Task.Execute () [0x00000] in :0

--- End of stack trace from previous location where exception was thrown ---

at Xamarin.Android.Net.AndroidClientHandler+d__45.MoveNext () [0x0012e] in <6f8818d6ffa14f4bad6fb5f5d0f0e665>:0

--- End of stack trace from previous location where exception was thrown ---

at Xamarin.Android.Net.AndroidClientHandler+d__40.MoveNext () [0x00230] in <6f8818d6ffa14f4bad6fb5f5d0f0e665>:0

--- End of stack trace from previous location where exception was thrown ---

at System.Net.Http.HttpClient+d__49.MoveNext () [0x000ca] in <25ebe1083eaf4329b5adfdd5bbb7aa57>:0

--- End of stack trace from previous location where exception was thrown ---

at System.Net.Http.HttpClient+d__55.MoveNext () [0x0007d] in <25ebe1083eaf4329b5adfdd5bbb7aa57>:0

--- End of stack trace from previous location where exception was thrown ---

at WDSRSApp.Services.RestService+d__6.MoveNext () [0x0005f] in D:\Projects\WDSRSApp\WDSRSApp\WDSRSApp\Services\RestService.cs:37

--- End of managed Javax.Net.Ssl.SSLHandshakeException stack trace ---

javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

at com.android.org.conscrypt.ConscryptFileDescriptorSocket.startHandshake(ConscryptFileDescriptorSocket.java:219)

at com.android.okhttp.internal.io.RealConnection.connectTls(RealConnection.java:192)

at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:149)

at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:112)

at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:184)

at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:126)

at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:95)

at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:281)

at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:224)

at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:461)

at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:127)

at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:89)

at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(Unknown Source:0)

Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:661)

at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:539)

at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:495)

at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:418)

at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:339)

at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:94)

at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:88)

at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:197)

at com.android.org.conscrypt.ConscryptFileDescriptorSocket.verifyCertificateChain(ConscryptFileDescriptorSocket.java:399)

at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)

at com.android.org.conscrypt.SslWrapper.doHandshake(SslWrapper.java:374)

at com.android.org.conscrypt.ConscryptFileDescriptorSocket.startHandshake(ConscryptFileDescriptorSocket.java:217)

... 12 more

Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

... 24 more

}