Update: 3/8/18, 10:00 a.m.: Oculus has provided instructions to fix the issue, which can be found here.
Affected users should go to https://www.oculus.com/rift-patch/ and download "OculusPatchMarch2018.exe." Allow it to run, including temporarily disabling antivirus if necessary (be sure to re-enable it afterwards) and then click "Repair" and restart the program. Everything should run as normal.
Oculus co-founder Nate Mitchell tweeted that users affected will get a $15 credit to the Oculus store.
The original story about the outage is below.
The issue reads "Can't Reach Oculus Runtime Service. Your Oculus software may be updating. Please wait a minute and try again. If the issue continues, contact Oculus Support."
Users digging in their files have found that a system certificate has expired. A temporary fix users have found is to move their system clock a few days back to when the certificate worked and then uninstall and reinstall Oculus software.
When reached for comment, Oculus directed us to a statement on its forums.
"We are aware of and actively investigating an issue impacting ability to access Rift software," it reads. "Our teams apologize for any inconvenience this may be causing you and appreciate your patience while we work on a resolution. We'll share more updates here as we have them. Thanks."
Oculus later confirmed that the issue has to do with the expiration of a security certificate, and is advising users to wait until it provides an official fix.
On Twitter, Oculus co-founder Nate Mitchell wrote that the company is resolving the issue.