Roundcube: connection reset by peer

Hi all,

I’ve got problems on one of our servers when users want to change their email password in roundcube.

"New password could not be saved. There is a connection error. Recv failure: Connection reset by peer"

Can’t find any error in any logfile (or perhaps I’m missing which log file I should look at). On other servers changing the password works fine. All servers share all the same settings (except for the ip addresses obviously).