In our environment we have 3 exchange mailbox servers 2 in our main office and 1 in a secondary site. We have 3 CAS servers behind a WNLB. Seems like for a few months now we have been having activesync issues. high CPU usage on the IIS process. I am seeing the event 1040 on the exchange servers. In trying to troubleshot I found this article and I checked my setting and they are the same. I asked my network admin about the firewall setting and he told me that the were no time values on the firewall. Any help appreciated. Tanks.