It may help if you share some more info. For example, - when you get the invalid password message, does it work when you reenter it? - does this happen for the two of you at the same time, or does one work when the other doesn't? - did this begin immediately after doing a Thunderbird update? - are you able to access email via a webmail interface?

It may help if you share some more info. For example, - when you get the invalid password message, does it work when you reenter it? Sometimes but not very often

- does this happen for the two of you at the same time, or does one work when the other doesn't? Not sure, we are not collocated in the same room.  Wife only has the one account and I have both from the same server

- did this begin immediately after doing a Thunderbird update? The last update that I’m aware of was on 5 July, this problem started about a week prior.

- are you able to access email via a webmail interface? Have not tried but both of our email accounts work fine on our phones.

Okay, please post a screenshot of your input server settings. That may help. The infrequent problem indicates a network reliability issue more than an email client issue. Does this happen frequently, such as many times a day, or rarely? If the password works sometimes, as you say, but not always, there is not a lot that can be done.

The email works reliably on the phone but has a problem with Thunderbird on the computer. The error messages appear every time Thunderbird pings the server every ten minutes for each of the two accounts and only infrequently is able to capture our email. Thunderbird worked fine for a number of years and suddenly has this problem for the last several weeks. And the fact that it happened to both my wife's and my computers at the same time says something changed with Thunderbird. If this doesn't get fixed I'll have no choice but switch over to the Windows email system which I would rather not do.

For a start, I suggest you switch your incoming server to port 995, change security to SSL/TLS and change your outgoing server to port 465 an SSL/TLS. You're sending password info insecurely and that is not a good connection. It may also help to include your full email address, not just the first component. Please do that and let me know. Those settings you are using are not recommended.

I inputted your recommendations for one of the two accounts with no improvement. I'm going back to original and input just one change at a time to see if this works. this will take awhile. Thanks for your help

Your suggestions were close. I went to the phone settings and inserted those and it works. See new image. Also changed outgoing to smtp.sitestar.net to smtp.everyone.net and SSL/TLS, port 465. Thanks again for your help you got me pointed in the right direction.

I was glad to assist. Thanks for feedback.