diff --git a/vector/src/test/java/im/vector/app/features/onboarding/OnboardingViewModelTest.kt b/vector/src/test/java/im/vector/app/features/onboarding/OnboardingViewModelTest.kt
index c612644576..216cb76084 100644
--- a/vector/src/test/java/im/vector/app/features/onboarding/OnboardingViewModelTest.kt
+++ b/vector/src/test/java/im/vector/app/features/onboarding/OnboardingViewModelTest.kt
@@ -48,6 +48,7 @@ import im.vector.app.test.fakes.FakeVectorOverrides
 import im.vector.app.test.fakes.toTestString
 import im.vector.app.test.fixtures.a401ServerError
 import im.vector.app.test.fixtures.aHomeServerCapabilities
+import im.vector.app.test.fixtures.anUnrecognisedCertificateError
 import im.vector.app.test.test
 import kotlinx.coroutines.test.runTest
 import org.amshove.kluent.shouldBeEqualTo
@@ -66,6 +67,7 @@ private const val A_DISPLAY_NAME = "a display name"
 private const val A_PICTURE_FILENAME = "a-picture.png"
 private val A_SERVER_ERROR = a401ServerError()
 private val AN_ERROR = RuntimeException("an error!")
+private val AN_UNRECOGNISED_CERTIFICATE_ERROR = anUnrecognisedCertificateError()
 private val A_LOADABLE_REGISTER_ACTION = RegisterAction.StartRegistration
 private val A_NON_LOADABLE_REGISTER_ACTION = RegisterAction.CheckIfEmailHasBeenValidated(delayMillis = -1L)
 private val A_RESULT_IGNORED_REGISTER_ACTION = RegisterAction.SendAgainThreePid
@@ -322,6 +324,25 @@ class OnboardingViewModelTest {
                 .finish()
     }
 
+    @Test
+    fun `given has sign in with matrix id sign mode, when handling login or register action fails with certificate error, then emits error`() = runTest {
+        viewModelWith(initialState.copy(signMode = SignMode.SignInWithMatrixId))
+        fakeDirectLoginUseCase.givenFailureResult(A_DIRECT_LOGIN, config = null, cause = AN_UNRECOGNISED_CERTIFICATE_ERROR)
+        givenInitialisesSession(fakeSession)
+        val test = viewModel.test()
+
+        viewModel.handle(A_DIRECT_LOGIN)
+
+        test
+                .assertStatesChanges(
+                        initialState,
+                        { copy(isLoading = true) },
+                        { copy(isLoading = false) }
+                )
+                .assertEvents(OnboardingViewEvents.UnrecognisedCertificateFailure(A_DIRECT_LOGIN, AN_UNRECOGNISED_CERTIFICATE_ERROR))
+                .finish()
+    }
+
     @Test
     fun `when handling SignUp then sets sign mode to sign up and starts registration`() = runTest {
         givenRegistrationResultFor(RegisterAction.StartRegistration, ANY_CONTINUING_REGISTRATION_RESULT)
@@ -550,6 +571,44 @@ class OnboardingViewModelTest {
                 .finish()
     }
 
+    @Test
+    fun `when editing homeserver errors with certificate error, then emits error`() = runTest {
+        fakeHomeServerConnectionConfigFactory.givenConfigFor(A_HOMESERVER_URL, fingerprint = null, A_HOMESERVER_CONFIG)
+        fakeStartAuthenticationFlowUseCase.givenErrors(A_HOMESERVER_CONFIG, AN_UNRECOGNISED_CERTIFICATE_ERROR)
+        val editAction = OnboardingAction.HomeServerChange.EditHomeServer(A_HOMESERVER_URL)
+        val test = viewModel.test()
+
+        viewModel.handle(editAction)
+
+        test
+                .assertStatesChanges(
+                        initialState,
+                        { copy(isLoading = true) },
+                        { copy(isLoading = false) }
+                )
+                .assertEvents(OnboardingViewEvents.UnrecognisedCertificateFailure(editAction, AN_UNRECOGNISED_CERTIFICATE_ERROR))
+                .finish()
+    }
+
+    @Test
+    fun `when selecting homeserver errors with certificate error, then emits error`() = runTest {
+        fakeHomeServerConnectionConfigFactory.givenConfigFor(A_HOMESERVER_URL, fingerprint = null, A_HOMESERVER_CONFIG)
+        fakeStartAuthenticationFlowUseCase.givenErrors(A_HOMESERVER_CONFIG, AN_UNRECOGNISED_CERTIFICATE_ERROR)
+        val selectAction = OnboardingAction.HomeServerChange.SelectHomeServer(A_HOMESERVER_URL)
+        val test = viewModel.test()
+
+        viewModel.handle(selectAction)
+
+        test
+                .assertStatesChanges(
+                        initialState,
+                        { copy(isLoading = true) },
+                        { copy(isLoading = false) }
+                )
+                .assertEvents(OnboardingViewEvents.UnrecognisedCertificateFailure(selectAction, AN_UNRECOGNISED_CERTIFICATE_ERROR))
+                .finish()
+    }
+
     @Test
     fun `given unavailable full matrix id, when a register username is entered, then emits availability error`() = runTest {
         viewModelWith(initialRegistrationState("ignored-url"))
@@ -726,7 +785,6 @@ class OnboardingViewModelTest {
                 .finish()
     }
 
-
     @Test
     fun `given in sign in mode, when accepting user certificate with SelectHomeserver retry action, then emits OnHomeserverEdited`() = runTest {
         viewModelWith(initialState.copy(onboardingFlow = OnboardingFlow.SignIn))
diff --git a/vector/src/test/java/im/vector/app/test/fakes/FakeStartAuthenticationFlowUseCase.kt b/vector/src/test/java/im/vector/app/test/fakes/FakeStartAuthenticationFlowUseCase.kt
index bfbef9e565..4b2709facc 100644
--- a/vector/src/test/java/im/vector/app/test/fakes/FakeStartAuthenticationFlowUseCase.kt
+++ b/vector/src/test/java/im/vector/app/test/fakes/FakeStartAuthenticationFlowUseCase.kt
@@ -31,6 +31,10 @@ class FakeStartAuthenticationFlowUseCase {
         coEvery { instance.execute(config) } returns result
     }
 
+    fun givenErrors(config: HomeServerConnectionConfig, error: Throwable) {
+        coEvery { instance.execute(config) } throws  error
+    }
+
     fun givenHomeserverUnavailable(config: HomeServerConnectionConfig) {
         coEvery { instance.execute(config) } throws aHomeserverUnavailableError()
     }
diff --git a/vector/src/test/java/im/vector/app/test/fixtures/FailureFixture.kt b/vector/src/test/java/im/vector/app/test/fixtures/FailureFixture.kt
index 0f44976ab3..8437401294 100644
--- a/vector/src/test/java/im/vector/app/test/fixtures/FailureFixture.kt
+++ b/vector/src/test/java/im/vector/app/test/fixtures/FailureFixture.kt
@@ -18,6 +18,7 @@ package im.vector.app.test.fixtures
 
 import org.matrix.android.sdk.api.failure.Failure
 import org.matrix.android.sdk.api.failure.MatrixError
+import org.matrix.android.sdk.api.network.ssl.Fingerprint
 import java.net.UnknownHostException
 import javax.net.ssl.HttpsURLConnection
 
@@ -38,3 +39,5 @@ fun aLoginEmailUnknownError() = Failure.ServerError(
 )
 
 fun aHomeserverUnavailableError() = Failure.NetworkConnection(UnknownHostException())
+
+fun anUnrecognisedCertificateError() = Failure.UnrecognizedCertificateFailure("a-url", Fingerprint(ByteArray(1), Fingerprint.HashType.SHA1))