Per the CEC:
Two upcoming maintenance events for the report generator are scheduled to occur within a 4-hour window between 10:00 p.m. 05/21/18, and 2:00 a.m. 05/22/18, and the following week between 10:00 p.m. 05/28/18, and 2:00 a.m. 05/29/18. Each disruption should last no more than 30 minutes. This means no CF1R, PRF-01, or XML files can be generated during the disruption period.
We do our best to perform updates at times that will have the least impact, but want to provide advance warning that could impact some users.