Migrating an environment from one LifeTime Server to Another


I am trying to de-register DEV environment from old Lifetime server and register it on New one.
When I register the environment, it gives me an error:

{{Sever URL}} :8043 couldn't connect back to the LifeTime environment

We tried to telnet to the server from new LifeTime environment and it works fine.

Apart from de-register from old lifetime and register on new lifetime, do I need to take any other step?


Another thread on forum talked about cleaning "SecurityManagerURL" site property value but even after that the issue did not resolve. 

Appreciate your help with this issue.