In case you're having an issue because of net glitch and pondering, how would I access my ATT Yahoo email account? At that point you should utilize the arrangements that you can get from the tech group by addressing them or you can associate with the assistance community and utilize their FAQs to determine the issue.
https://www.numbersupportcustomerservice.com/blog/access-my-att-email-account/
Make sure your email:
Meets maximize message size limits.
Includes the correct recipient email address. If it doesn’t, you may get error messages like Failed Delivery or Problem Found - Message Not Sent.
Sign out of your email account, and then sign back in.
Check your spam folder for missing messages.
To review your settings, select the gear icon:
Blocked addresses: Make sure you aren’t blocking addresses you want to get email from.
Filters: Make sure emails are going to the correct folder.
Confirm you haven’t been hacked. Your account may be compromised if you’re:
Missing emails
Getting emails from your own email address
Getting complaints about spam coming from your email address
Seeing a display name that's different from the one you set up.
I hope these steps will be helpful!
Mark Wilson