Persistent nSght VSE connection error 0x80004005

Win10 laptop core i7 16 GB GTX680M. Using CUDA with VS2015 and VS 20217. Just installed nSight (2019.3.0) for the first time. Both VS versions show nSight as installed. But when I try to start the NextGen nSight debugger I get message “unknown error 0x80004005”.

Several other users have reported this problem and apparently resolved it. But none of them has said how.

I have already done the following, without success:
– opened TCP/UDP ports 4500-4510 in Windows Firewall and AVG firewall, incoming and outgoing
– installed Windows KM-TEST loopback network adapter
– checked for corrupted system files

BTW the legacy nSight debugger runs, however it seems to be ignoring the breakpoints I set in VS. That is the subject of a different post.