I am not able to do Impact Analysis of my CDT. Its is showing server encounter s

If this happening for any CDT and you DO NOT see any errors in the server.log then this can indicate the error is being thrown at the client side. This can happen if you have a large amount of applications (or small amount but big applications) since Impact Analysis will review each item inside them the request on the server can take longer and timeout on the client; by when the server completes the client already timed out with the error you're seeing.

To address the issue delete any unnecessary applications from the Applications tab, most of the times there will be several that were used to bring objects from another environment and after the import are no longer needed; delete those.

If this happening for any CDT and you DO NOT see any errors in the server.log then this can indicate the error is being thrown at the client side. This can happen if you have a large amount of applications (or small amount but big applications) since Impact Analysis will review each item inside them the request on the server can take longer and timeout on the client; by when the server completes the client already timed out with the error you're seeing.

To address the issue delete any unnecessary applications from the Applications tab, most of the times there will be several that were used to bring objects from another environment and after the import are no longer needed; delete those.