Hi... Here you go Visit this Web site and follow the steps. http://support.microsoft.com/default.aspx?scid=kb;en-us;842273 If that fails disable all the AV and spam software on both the ends. This is necessary as the replication message are blocked sometime by these software as it thinks its a spam or some virus. If the issue poersist, please follow the steps given below. Click Start, click Run, type regedit , and then click OK. Expand the following registry key: HKey_Local_Machine\System\CurrentControlSet\Services\MSExchangeTransport 1. Right-click MSExchangeTransport , point to New, and then click Key. 2. Type Parameters , and then press ENTER to name the new key. 3. Right-click Parameters , point to New, and then click DWORD value. 4. Type SkipPublicMDBRestriction , and then press ENTER to name the value. 5. Double-click SkipPublicMDBRestriction . 6. In the Value data box, type 1 , and then click OK. 7. Close Registry Editor. Make the registry changes on both the sending and receiving server This should resolve the issue. If not please let me know. Manoj Enterprise Messaging Support