Atlassian have indicated that the platform issue has been resolved. Testing shows that Comala Canvas for Confluence Cloud is now working again.
Jun 18, 02:54 PDT
The problem affecting Comala Canvas for Confluence Cloud (as well as other Confluence Apps) is related to a platform issue.
We will provide updates here as they become available. If you would like to monitor the Atlassian related issue directly, please watch: https://jira.atlassian.com/browse/CONFCLOUD-60133
Jun 17, 17:34 PDT
We are currently investigating an issue with Comala Canvas for Confluence Cloud that is preventing boards from rendering on pages.
Jun 17, 05:36 PDT