Odd Bellsouth.net Domain Email issues just starting...

1. My WIFE - MOST important - we moved and no longer have ATT, but loved it and my Fathger-In-Law Retired with you guys, but we don't have access after moving. My wife got an iPhone 13, I think. Her mail app will no longer receive email from her Bellsouth.net account. She also uses Outlook 2013 on Win 10 and it typically works well (not sure at the moment). She does NOT use the Web Interface at yahoo, but last I checked there were 2 different passwords required for Outlook and the web interface.. She is losing her mind with her iPhone mail app which was working 3 days ago and nothing on the phone changed, except she cleared so many pics and messages that she has a ton of free space. I read about someone needing a authentication or device or PKI type key and having to delete their account, but not sure that matters.

2. Me - I ONLY use the Web Interface for my bellsouth.net domain email account. Seems to work good most days. I cant do some things I'd like without paying, but I also have a gmail account that I am trying to switch to which will allow me to kill my bllsouth,net account. My biggest problem at the mokment is that since a few days back, if I send myself an email to my bellsouth.net acct FROM my gmail account, I NEVER receive it - yes I checked SPAM and I was receiving messages back in January, so how do we troubleshoot this?

Any assistance is most appreciated !