[fetchmail]"SMTP connect to [hostname] failed"

Some days ago my fetchmail (5.4.0) started to say
---snip---
fetchmail: SMTP connect to rechner failed
fetchmail: SMTP transaction error while fetching from pop3.freenet.de
---snip---
and die whenever it tries to fetch a mail from a POP3 server. ('rechner' is my 
hostname.)
I don't think I have changed any relevant configuration files and it has worked 
very well before...

The POP3-Server is ok. I can fetch the mail with other programs (e.g. mutt).

Any suggestions?
Tobias Wichtrey