Users ProxyAddresses do not synch accross
The DSA.LOG contains the error "COM AcAdSwitches Warning: object CN=C5149336,CN=Users,DC=sap,DC=lab has invalid proxy address: test_Biswaroop@lab.com"
The address is invalid. In this Case addresses were set in adsiedit without smtp: prefix.
Add the smtp: prefix to the proxy address.