UDN problems

[Terence Kumar_1]

hi
My SPOP has more than 240 clients configured properly. My UDN service also shows the same but i notice 2 problems.
1. When i do a test notification via email, i dont receive the email. This is from the Health Info menu in the UDN screen.
2. Also, when i changed the IP of one of my clients, it is detected correctly by the Enterprise View after client reinstall, but UDN still detects the old ip!. And when i disable and try to delete the client from UDN, i get an error at the bottom left corner of the Internet Explorer.

Hope someone can help.

tks
terence