squirrelmail hangs on send

I have squirrelmail running on FC6 with ispconfig for quite a while, this works nicely except that sometimes squirrelmail hangs when sending messages. if you hit the send button it keeps waiting forerver, sometimes the message gets send, but you don't get a reply, sometimes the message does not get sent at all. lately the situation has gotten worse, without any changes to the config,

any help is welcome,

best regards,

Herwig

 

Are there any errors in /var/log/maillog when this happens?

 

i don't see anything, but when i change the options of squirrelmail so that it does not move the sent items to the sent folder but specify 'do not use sent' then it works immediately. so its likely to be some security issue somewhere.

 

Could be a permissions problem (e.g. Squirrelmail tries to create the "Sent Items" folder, but isn't allowed to do so).