This POP3 server 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.
Iste servitor POP3 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.