Cannot login, send, or receive emails at my att.net address
When I attempt to login to my att.net email on the web, I receive the following message:
"Not found on Accelerator. Description: Your request on the specified host was not found. Check the location and try again."
On my IPad and iPhone, I cannot send or receive emails and I receive a message saying my
username and password are incorrect.
I have not changed my username, password, or iPad/iPhone mail settings. Why is this happening? It is as if my att.net email account has vanished, been deleted, or never existed.