There is a major incident open on that (incident 46648). RC found the problem and is implementing the change to fix it now. It is impacting login to the portal.
RingCentral Service Status Update
Incident Summary:
A portion of RingCX customers may be experiencing login issues.
Start Time:
Feb 12, 08:06 PST
Update:
RingCentral Operations teams have identified a potential cause of the issue and are currently rolling back a recent release. If you are experiencing this issue, please reach out to customer care. The next update will be provided in 4 hours or when a significant change in status occurs.