We detected a higher-than-normal error rate in Canvas at about 11:30 PM Mountain Time this evening (6:30 AM on 23 January UTC). Several users reported seeing error messages when trying to view pages or submit assignments between 11:30 PM Mountain Time and 11:45 PM Mountain Time (between 6:30 AM and 6:45 AM on 23 January UTC).
Our DevOps team investigated and identified the source of the issue: a shared infrastructure element that did not recover as quickly as expected from a routine maintenance action that should not have had any impact on users. We apologize for the trouble. We'll review the process around the routine action and identify any improvements we can make to ensure that future, similar actions don't impact users.