Apologies that you have not received a response to this question when you posted it before (#1073971, #1074640).

Could you remind me how this works? You start MailWasher and look at what is on the server, you mark what you want to delete, and MailWasher deletes it. What happens next -- you start Thunderbird and Thunderbird connects directly to the server (not to MailWasher itself) and retrieves whatever new mail is left on the server, completely unaware of what MailWasher might or might not have done?

Does Thunderbird give you any error messages, or does it act as though there isn't any new mail to retrieve, or is it stuck "connecting"?

If Thunderbird won't connect to your mail server, it probably is completely unrelated to MailWasher and could be related to an update. One common reason for that might be that firewall software detected the change and is blocking the new version.

As far as I know the mailwasher is directly linked to Mozilla. After mail is washed it goes directly to the thunderbird program. About a week ago this stopped happening. No mail is forwarded after being washed. Error message states that it cannot connect to server or email address or password is wrong.

Mozilla.org has nothing to do with the separate Mailwasher software.

Mozilla also refuses to accept mail directly from the server. "configuration error account or password incorrect"

Could you check your account settings and make sure they are current? Is this a Gmail account? Thunderbird recently added support for Google's higher security requirements but you would need to modify how your account is set up.

RebelRon said

Mozilla also refuses to accept mail directly from the server. "configuration error account or password incorrect"

Mozilla (mozilla.org) themselves does not do email services with public.

Also even though Thunderbird is still called Mozilla Thunderbird it is no longer a Mozilla product as it is being done by a community.

Mozilla Firefox or Firefox is however a Mozilla product.