If you had attempted to sync your outgoing mail server settings through Send Direct and encountered an error, there are a few different things that may have occurred during your sync. The specific message the error code mentions will give us a hint to what is causing the sync to fail.
You may see...
"An error occurred":
This error usually means that the outgoing mail server information you had entered for your email provider was incorrect. If a connection to the mail server cannot be established (the connection doesn't exist, the mail server refuses the connection, etc.), this generic error will be thrown.
"An error occurred. SMTP Error: Could not authenticate":
This error is more specific, and indicates that a connection to your outgoing mail server can be made, but the server cannot verify that your log in credentials are accurate. The most common causes of this are either a forgotten or mistyped username or password being entered into the Username and Password fields in Send Direct.
Other causes of this can be due to the use of multi-factor authentication software (MFA) being used on that mail server. If you normally enter your password, as well as an additional code to access your email account, this would be considered multi-factor authentication. Send Direct is not able to sync your settings correctly with multi-factor authentication in place.
Additionally, is it also possible that a login would be refused if the security standards for your outgoing mail server do not allow incoming connections or connections from external sources. Mostly this effects businesses and corporate level users, but can also affect single users depending on the security standards of the mail provider.