Can anyone assist with this error? I am not sure what is wrong as I am logging into the email account with the same password that myBB is using.
which SMTP server you are using ? has it worked earlier & suddenly stopped working ?
I am using the one advised by my mail client (provided by my host). I am unsure if it has just suddenly stopped working or not
Check the admin email address configuration in the ACP > Configuration. Some hosts require you to use the same email address there as the email account you're sending from. Both that setting and the SMTP username should be the same.