Temporary Error 15 is usually a symptom of Yahoo’s own infrastructure hiccups, but taking a few proactive steps — switching ...

Yahoo Mail suffers massive outage with 'Temporary Error 15' affecting thousands of users unable to access emails or login to their accounts.

Some users also noted that AOL Mail, another email service owned by Yahoo’s parent company, was down at the same time. “The most frustrating thing is not getting acknowledgment.