One day you can access your email account and the next you cannot. Using the “forgot password” link is no help and calling tech support is no help. What happened?!
Most likely the service account associated with the email address is no longer valid and the email server swiped your account out of existence. No warning. Gone.
This happened to a client of ours who used a sbcglobal.net email address. They had the address for years, even decades. It was setup way back when they had a cable account or, in this case, a dsl account with AT&T or another phone service. The service was discontinued but the email remained active until the email server swiped the account. In this case, Yahoo was used to access the sbcglobal.net email. Yahoo has been sold several times over the years with each sale increasing the risk of losing it all. Since the email account was not associated with any active service agreement it was deleted.
To prevent this from happening we strongly suggest using an email account that is stand alone, not associated with a service. Gmail for example, would be a great choice.