The operator reported issues with the remote access control system. It was repeatedly asking for his credentials. I was able to walk him through adding a user to the system so that he could get some help brining with the IFO. I also was granted access. I restarted the apache instance on cdsadminctrl after reproducing the operators issue. This appears to have solved the issue. Apache was not able to negotiate the authentication. Cause currently unknown. I've opened an FRS to remind me to look at it in the morning. See FRS https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=7677