One email account fails to display inbox on one PC. It works fine on a second PC so it is not a problem with the email account.
When I set up this email account on one PC it fails with Unknown Command. This email address works fine using Thunderbird on a second computer. It used to work on this computer also but now does not. Clearly something has been left over from a previous install and now although Thunderbird sets the account up OK, the inbox does not open. Each time I get Unknown command followed by some characters, which change every time I try to access the inbox.