Hello Group, I have got following error in eventlog every 15 minutes. Source: MSExchange Web Service Category: Core Event-ID: 12 Caller S-1-5-20 attempted to proxy EWS traffic to MAILSERVER. This failed because the calling AD account does not have the necessary access rights to send EWS proxy traffic to MAILSERVER We are using W2k3 R2 and Exchange 2007 Yesterday I created a new site because we have added a third DC in our domain in another location. I created a new site and moved the thrid DC into this site. I created subnets and linked them. I think the error has something to do with the new site creation but i don`t know where i have to look to eliminate this error. thanks for all helpfull ideas

where are u getting this error? is that DC a GC also?

I am getting this error on our mailserver. It`s a w2k3 server r2 with exchange 2007. This server is only a member server.

Is the DC in the new site a GC also? How many ex servers do u have? What is the role of the Ex server that enerating the error, CAS? DO u have exhcage servers in the new site also? see here: http://social.technet.microsoft.com/Forums/en-US/exchangesvrgeneral/thread/25577820-0d37-4ce9-ab2c-9956abe44317 http://arstechnica.com/civis/viewtopic.php?f=17&t=34401 http://support.microsoft.com/kb/243330/en-gb - to see the SID S 1-5-20: its netowrk service Its a persmission issue, u gota isolate to see what is trigering it. And when it started.

Hello, yes, the new dc in the new site is also a gc. we have got only one exchange in our site. he is in the "old" site and not in the new site. How can I isolate the permission issue?

When i say to "isolate" the issue,i mean u gota see what is triggering it, what is the cause. Did u have it before the new ad site, or after, does it happen when a user whants to use OWA, or just connect to exhange with Outlook etc... Did u run ExBPA does it have any errors? Also the error that u are getting is stating that your Network service doesnt have rights to send the proxy traffic. Does this error affect your users in any way? http://arstechnica.com/civis/viewtopic.php?f=17&t=34401 also did u check this aritcle? What version of Exhcnge 2007 do u have? I sugest going to SP2 if u havent, or even SP3. SP2 roleup2 has a fix for a simular issue

Hello ZarkoC, with your help i solved the problem. In exchange management console there was the data for the external url in client access missing. i filled in the external url and the error was gone. Thanks a lot for your help!

No problem, all the best. Zarko