We know this is an error that might give us a hard time, not understanding what it means. But this article comes in handy regarding the meaning of this error. It mainly means that due to connection ports used. We would always advise using SMTP port 465 or 587.
Timeout Errors: These can occur due to a slow internet connection, a low timeout value, too many simultaneous connections, or antivirus or firewall blocking outgoing traffic. Increasing the timeout value, reducing the number of simultaneous connections, and checking firewall and antivirus settings can help resolve these issues.
Disconnection Errors: These may happen because of too many simultaneous connections to the SMTP server or a timeout on the email marketing software’s side. Lowering the number of simultaneous connections and increasing the timeout value can mitigate these errors.