I've copied my claws mail configuration (~/.claws-mail directory, one imap account) to another PC. Viewing Mails just works out of the box, but every time I try to send a message, claws mail throws an error and does not send it: (en) Could not queue message for sending (de) Nachricht konnte nicht f
Check your account parameters. You may have specified a nonexisting Queue folder in the Advanced tab.