"An error occurred when trying to open the SOLIDWORKS PDM URL. You don't have permission to perform this action."

I have had this error on other users before, but I can't seem to remember how to fix it. I have checked the user's group permissions and everything looks to me to be in order. I have had him exit the vault; log off his computer and restart with no success. Can someone please refresh my memory on how to solve this?

Thanks in advance.

SolidworksSolidworks Pdm/enterprise Pdm