Mail Stopped Both Ways — "451 Temporary Local Problem" and the One DNS Resolver Nobody Checked

A presales war story about a cPanel server that could neither send nor receive mail — no blacklist, no full disk, no broken config — and the single DNS line I now check before I open any mail log. The call was short. "Email is down. Completely. We can't send, and nothing is coming in." The server was a customer's cPanel/WHM box on Rocky Linux 8.... Weiterlesen: Mail Stopped Both Ways — "451 Temporary Local Problem" and the One DN…