3 ms·
Their SMTP server being unreachable is a 4xx temporary error. The sender MUST keep trying for at least 24 hours, and 72 hours is recommended. "Gmail going dow
by octoberfranklin 6y ago
Their SMTP server being unreachable is a 4xx temporary error. The sender MUST keep trying for at least 24 hours, and 72 hours is recommended.
"Gmail going down" would not have caused this problem. Even if all their SMTP servers went offline.
- organsnyder 6y agoYeah, they would have been better off pulling the (metaphorical) plug—maybe block incoming traffic to port 25 or something—until they had this fixed.