https://www.theverge.com/2018/3/7/17092084/oculus-rift-headsets-stopped-working-expired-certificate

Oculus Rift users today found that their headsets were not working, and the problem appears to be a single expired certificate, as reported by Neowin. The certificate, which is part of the Oculus Runtime service, is being read as invalid, and the cause is likely a simple mistake like someone forgetting to push out a new file.

The file causing issues is called OculusAppFramework.dll and needs to be updated in order for the headsets and software to run as normal. The error message users are seeing as a result says, “Your Oculus software may be updating. Please wait a minute and try again. If the issue continues, contact Oculus support.”