Not able to catch error of changing Firebase User email - firebase

Question

Since hours I have an Problem with my method. When trying to update use email and the email really exists its works fine. But when I pasting just any sh-- its giving me an error in console but not returning anything . Please help
This is my method
//update in with passwort and email
Future updateemail2(String email, String password, String newemail) async {
try {
UserCredential authResult =
await _auth.currentUser.reauthenticateWithCredential(
EmailAuthProvider.credential(
email: email,
password: password,
),
);
User user = authResult.user;
if (user != null) {
user.verifyBeforeUpdateEmail(newemail);
// user.sendEmailVerification();
}
// user?.emailVerified;
} on FirebaseAuthException catch (e) {
switch (e.code) {
case 'invalid-email':
{
return 'Email ist nicht gültig';
}
case 'email-already-in-use':
{
return 'Email bereits registriert';
}
case 'wrong-password':
{
return 'Passwort ist nicht gültig';
}
case 'internal-error':
{
return "internal error";
}
default:
{
return 'Unexpected Error';
}
return null;
}
}
return null;
}
Im calling it like that
buildupdate(context, userData, user) async {
if (_formKey.currentState.validate()) {
String authError4 = await _auth.updateemail2(
userData.email, userData.password, _currentemail);
if (authError4 != null) {
setState(() {
showerror = true;
error = authError4;
});
} else {
print("halts maul");
}
This is the error which im not able to catch