Are you not able to send emails by using your AT&T account? And are you also not able to receive an email by using AT&T account? If your answer is yes then you have to check whether you are entering the correct recipient email address. Even you have to check whether you have blocked or not the email address of the client from which are accepting emails. You can try to use any other web browser for accessing your AT&T account. Even after trying all these steps if the error is not solved then just dial the AT&T Email Customer Support Number where experts will help you in fixing the issue faced by you. Read more : ATT Email Customer Service | ATT Email Tech Support phone number | ATT Email Customer Support phone number