diff --git a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsController.kt b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsController.kt
index 3dda8f5e35..331bff0b4a 100644
--- a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsController.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsController.kt
@@ -25,6 +25,7 @@ import com.airbnb.mvrx.Success
 import im.vector.app.R
 import im.vector.app.core.epoxy.loadingItem
 import im.vector.app.core.epoxy.noResultItem
+import im.vector.app.core.error.ErrorFormatter
 import im.vector.app.core.extensions.exhaustive
 import im.vector.app.core.extensions.getFormattedValue
 import im.vector.app.core.resources.ColorProvider
@@ -37,12 +38,15 @@ import im.vector.app.features.discovery.settingsEditTextItem
 import im.vector.app.features.discovery.settingsInfoItem
 import im.vector.app.features.discovery.settingsInformationItem
 import im.vector.app.features.discovery.settingsSectionTitleItem
+import org.matrix.android.sdk.api.failure.Failure
+import org.matrix.android.sdk.api.failure.MatrixError
 import org.matrix.android.sdk.api.session.identity.ThreePid
 import javax.inject.Inject
 
 class ThreePidsSettingsController @Inject constructor(
         private val stringProvider: StringProvider,
-        private val colorProvider: ColorProvider
+        private val colorProvider: ColorProvider,
+        private val errorFormatter: ErrorFormatter
 ) : TypedEpoxyController<ThreePidsSettingsViewState>() {
 
     interface InteractionListener {
@@ -116,7 +120,7 @@ class ThreePidsSettingsController @Inject constructor(
                         }
                     }
 
-                    pendingList.forEach { buildPendingThreePid("p_email ", it) }
+                    pendingList.forEach { buildPendingThreePid(data, "p_email ", it) }
                 }
 
         when (data.state) {
@@ -171,7 +175,7 @@ class ThreePidsSettingsController @Inject constructor(
                         }
                     }
 
-                    pendingList.forEach { buildPendingThreePid("p_msisdn ", it) }
+                    pendingList.forEach { buildPendingThreePid(data, "p_msisdn ", it) }
                 }
 
         when (data.state) {
@@ -222,7 +226,7 @@ class ThreePidsSettingsController @Inject constructor(
         }
     }
 
-    private fun buildPendingThreePid(idPrefix: String, threePid: ThreePid) {
+    private fun buildPendingThreePid(data: ThreePidsSettingsViewState, idPrefix: String, threePid: ThreePid) {
         threePidItem {
             id(idPrefix + threePid.value)
             // TODO Add an icon for emails
@@ -253,6 +257,7 @@ class ThreePidsSettingsController @Inject constructor(
                     id("msisdnVerification${threePid.value}")
                     inputType(InputType.TYPE_CLASS_NUMBER)
                     hint(stringProvider.getString(R.string.settings_text_message_sent_hint))
+                    errorText(getCodeError(data, threePid))
                     interactionListener(object : SettingsEditTextItem.Listener {
                         override fun onValidate() {
                             interactionListener?.submitCode(threePid, currentCodes[threePid] ?: "")
@@ -271,4 +276,17 @@ class ThreePidsSettingsController @Inject constructor(
             }
         }
     }
+
+    private fun getCodeError(data: ThreePidsSettingsViewState, threePid: ThreePid.Msisdn): String? {
+        val failure = (data.msisdnValidationRequests[threePid.value] as? Fail)?.error ?: return null
+        // Wrong code?
+        // See https://github.com/matrix-org/synapse/issues/8218
+        return if (failure is Failure.ServerError
+                && failure.httpCode == 400
+                && failure.error.code == MatrixError.M_UNKNOWN) {
+            stringProvider.getString(R.string.settings_text_message_sent_wrong_code)
+        } else {
+            errorFormatter.toHumanReadable(failure)
+        }
+    }
 }
diff --git a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewModel.kt b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewModel.kt
index 78b20fc26d..0501d77808 100644
--- a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewModel.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewModel.kt
@@ -18,7 +18,9 @@ package im.vector.app.features.settings.threepids
 
 import androidx.lifecycle.viewModelScope
 import com.airbnb.mvrx.ActivityViewModelContext
+import com.airbnb.mvrx.Fail
 import com.airbnb.mvrx.FragmentViewModelContext
+import com.airbnb.mvrx.Loading
 import com.airbnb.mvrx.MvRxViewModelFactory
 import com.airbnb.mvrx.ViewModelContext
 import com.squareup.inject.assisted.Assisted
@@ -141,6 +143,14 @@ class ThreePidsSettingsViewModel @AssistedInject constructor(
 
     private fun handleSubmitCode(action: ThreePidsSettingsAction.SubmitCode) {
         isLoading(true)
+        setState {
+            copy(
+                    msisdnValidationRequests = msisdnValidationRequests.toMutableMap().apply {
+                        put(action.threePid.value, Loading())
+                    }
+            )
+        }
+
         viewModelScope.launch {
             // First submit the code
             session.submitSmsCode(action.threePid, action.code, object : MatrixCallback<Unit> {
@@ -151,9 +161,14 @@ class ThreePidsSettingsViewModel @AssistedInject constructor(
                 }
 
                 override fun onFailure(failure: Throwable) {
-                    // Wrong code?
                     isLoading(false)
-                    _viewEvents.post(ThreePidsSettingsViewEvents.Failure(failure))
+                    setState {
+                        copy(
+                                msisdnValidationRequests = msisdnValidationRequests.toMutableMap().apply {
+                                    put(action.threePid.value, Fail(failure))
+                                }
+                        )
+                    }
                 }
             })
         }
diff --git a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewState.kt b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewState.kt
index 47590286e0..4233ee1005 100644
--- a/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewState.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/threepids/ThreePidsSettingsViewState.kt
@@ -25,5 +25,6 @@ data class ThreePidsSettingsViewState(
         val state: ThreePidsSettingsState = ThreePidsSettingsState.Idle,
         val isLoading: Boolean = false,
         val threePids: Async<List<ThreePid>> = Uninitialized,
-        val pendingThreePids: Async<List<ThreePid>> = Uninitialized
+        val pendingThreePids: Async<List<ThreePid>> = Uninitialized,
+        val msisdnValidationRequests: Map<String, Async<Unit>> = emptyMap()
 ) : MvRxState