diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/failure/Extensions.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/failure/Extensions.kt
index 6e198fb98c..68b931b33c 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/failure/Extensions.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/failure/Extensions.kt
@@ -62,7 +62,10 @@ fun Throwable.isUsernameInUse() = this is Failure.ServerError &&
         error.code == MatrixError.M_USER_IN_USE
 
 fun Throwable.isInvalidUsername() = this is Failure.ServerError &&
-        error.code == MatrixError.M_INVALID_USERNAME
+        (error.code == MatrixError.M_INVALID_USERNAME || usernameContainsNonAsciiCharacters())
+
+private fun Failure.ServerError.usernameContainsNonAsciiCharacters() = error.code == MatrixError.M_UNKNOWN &&
+        error.message == "Query parameter \'username\' must be ascii"
 
 fun Throwable.isInvalidPassword() = this is Failure.ServerError &&
         error.code == MatrixError.M_FORBIDDEN &&