Error: SMTP Error 543

What's Causing This Error

SMTP error code 543 occurs when no route is available from the sender's email server to the recipient's email server. It is probably due to routing issues that deny traffic or when the email server cannot find routes to reach the recipient's email server.

Solution - Here's How To Resolve It

To resolve this error, ensure that there are active routes from the sender's email server to the recipient's email server. It is crucial to ensure a stable route for the port responsible for communicating the email traffic. However, checking network connectivity by pinging the recipient's email server may not be sufficient.