What brand is it? I had the issue with an HP mobile workstation a couple of years ago. Was quite old (ivy bridge generation). Exactly the same problem adding ram, no boot, removing it. Problem remained the same).
II was lucky enough it had 4 years support and I called the hotline. The guy was very helpful and it was quite a common problem. The bios did not like the new RAM.
There is a sequence to do with power button athat resets the bios to factory settings. Can't remember the exact sequence though, but it fixed the issue.