Sorry... the "huge mail problems" are not with the plesk server. They are occurring on a spam appliance further down the chain, hence there are no errors that would be relevant to plesk to post here!
Prior to the Plesk Onyx update that introduced SRS all our mail filtering worked fine but since then we are having major problems with whitelisting addresses etc as it does not yet understand SRS.But this is not the fault of the Plesk server, which is why I didn't put any more information in here!
I simply want to be able to switch off SRS, if that's possible!
We are using postfix and dovecot. Relaying is closed. We are using mail limitation.No DMARC. No DKIM. We are using SPF and DNSRBL.
I just didn't think any further information was relevant as the issue is not with Plesk... I literally want to know if SRS can be switched off in some way!!
If any specific information would help then I will gladly post it here but I'm really not sure what would be relevant!
Thanks for any help.