The IMAP server %S does not seem to support encrypted passwords. If you just set up the account, please try changing to 'Password, transmitted insecurely' as the 'Authentication method' in the 'Account Settings | Server settings'. If it used to work and now suddenly fails, this is a common scenario how someone could steal your password.
Le servitor IMAP %S non pare supportar contrasignos cryptate. Si tu ha justo ora configurate iste conto, tenta cambiar a 'Contrasigno, transmittite sin securitate' le 'Methodo de authentication' in 'Parametros de contos | Parametros de servitor'. Si illo functionava antea e ora subito falle, es possibile que alcuno tenta furar tu contrasigno.