CircleCI would be upgrading one of their core database instances on Saturday, March 27, 2021.
To do this, they will stop processing pipelines and workflows for up to 1 hour and 30 minutes from the hours of 16:00 to 17:30 UTC (12 p.m. to 1:30 p.m. ET / 9 a.m. to 10:30 a.m. PT).
After this period, you will be able to re-run any missed work by pushing a new commit or triggering via the API.
Please see more details about the maintenance here : https://discuss.circleci.com/t/database-maintenance-saturday-march-27-2021/39315
Or subscribe to status updates here: https://status.circleci.com/