since some time we are being regularly blocked by backscatterer (Backscatterer.org powered by UCEPROTECT). I am quite new to Zimbra and do not want to screw postfix so fast. Has anyone had such problem as well and is there any suggestions on how to prevent blocking there?

As far as I understand from the description, I am most likely being blocked because of bounce-back emails, which are being generated by Zimbra, instead incoming connection being blocked at once.

I would appreciate any help.