iPhone 16 Mail app repeatedly stops updating Gmail

My mom’s iPhone 16 is being a pain in my ***. She has her Gmail added in the mail app so she can view her emails there. She doesn’t have the Gmail app on her phone. Every now and then, it quits updating and gives the below message. Everything is correct (username and password) and there is no prompt to re-enter password either. To fix this, I have to go in and delete the email, re-add it, and then it updates. She has been to Verizon, and they say they can’t fix it, that she has to call a 1-800 number and apparently she can’t understand anyone she gets. I have re-added the email using the “other” option and added in the imap and the smtp and it doesn’t update (it shows no email, which isn’t accurate). I fetch new data and still nothing. I am getting tired of this because I know she won’t go through and delete it and re-add it and then she gets mad because it “won’t update”. It shouldn’t be acting like this and I am finally done trying to google it and try those fixes. Any idea as to why it’s doing this?