it is a @Onetel.net address. I had this issue about a month ago and it produces the error message:
I have login saved by Google so never need to enter username and password. Mail was working yesterday
Do you think it's possible that your saved password has been corrupted or the wrong password has been saved? You can view Saved Logins in Google Chrome browser via the Security & Privacy Setting.
If you know the password just clear the login boxes and enter manually.
Let us know if that works.
...I'll request a fault ticket.
To link this topic to your TalkTalk service please check your Community Profile includes in Personal Information (Click here):
Your name, current landline 'phone and alternate number (mobile preferred). Add full address with postcode (location). Then scroll down to Private notes to add email address(es), notes and references etc and then save changes.