I just tried installing the latest version of V-Ray (52004) with Rhino 7.15.22039.13001 and when starting Rhino I get the following error message:
How can I proceed here?
Just looking at V-Ray’s log file and I spotted this error:
Didn’t you just change your URL from chaosgroup.com to chaos.com ? Could it be that it is trying to look at a URL that does not exist? Although I would assume that you have set your DNS to correctly forward all old domains to the new ones.
I tried installing the previous version and get the same error there now 
Hello,
Can you please try to do the following and see if it will help:
1. Start Rhino
2. Open Windows Explorer and navigate to C:\Program Files\Chaos Group\V-Ray\V-Ray for Rhinoceros\V7
3. Drag the file named VRayForRhino.rhp from the folder with your left mouse button and drop it in Rhino`s viewport
4. Try using V-Ray, if it works restart Rhino and see if V-Ray will load automatically if it’s not loading automatically then in Rhino click on the drop-down menu Tools -->Options -->Plug-ins. Find V-Ray right-click on it and make sure that the Load Protection is disabled.
5. Restart Rhino and see if the plugin loads.
If this does not help, please create a ticket here: https://support.chaos.com/hc/en-us/requests/new
Thank you, Aneliya.
The steps you wrote worked and I can once again render with V-Ray.
Have a nice day!