"Could not send message using Email to user ID ###" error in log on all messages even though message is created successfully

This is the only message I could find that is similar to the one you reported. It may have changed since the issue was reported.

Could not send notification using the "email" notifier.

This happens inside the send method:

$notifier->send($message);

Is the error still occurring?

We had mailsafety installed and enabled as well and is the source of the issue, it appears.

Automatically closed - issue fixed for 2 weeks with no activity.