You could try changing when OFFLINE OR Move whatever mail you have in that account to a Local folders and set up a new account with the new settings.

Thank you for your reply. I can not even create a new user as when click on Account Settings Thunderbird freezes and Account Settings does not open. Thunderbird is frozen and no effort will close . The only way to close is using Task Manager and close the process. I downloaded the last version of Thunderbird and it did not solve the problem

Any other solution is more than welcome.

Try running Thunderbird in safe mode (add-ons are disabled) Hold down SHIFT when you start Thunderbird. Don't mark any boxes just continue in safe mode. If it works then your problem is in an add-on, You have to activate them one by one

Thank you Gnospen,

It did work. I now need to activate the add-ons one by one.

Thank you