The server is unable to connect or start an SMTP session.
Causes
Usually point to a configuration problem.
- For example, incorrectly spelled the SMTP Server, IP Address that does not exist, or the SMTP port is not exist, where the recipient will not receive SMTP connections, or some other process is already using the SMTP port.
Fixes
Step 1: Change The Server Name
Try to change the server name or connection port.