Tests have stopped running

The issue has been resolved by uninstalling and reinstalling the plugin.

It may have been caused by syncing staging, dev and production environments on WP Engine.

While pulling to a staging or dev environment shouldn’t lead to issues, pushing from a staging or dev environment to production would result in problems. This is because the test runs are bound to the specific URLs of a website. When the test URLs on production get overwritten with the test URL from staging, the production tests get unscheduled.

This can be prevented by excluding the VRTs db tables when syncing to production.
See the docs for the specific tables: https://vrts.app/docs/#multiple-environments

WP Engine can be configured to only sync specific db tables: https://wpengine.com/support/copy-site/#Specific_database_tables_only
And WP Migrate has an option to select tables as well: https://deliciousbrains.com/wp-migrate-db-pro/doc/importing-wordpress-local-development-environment/

I’m sorry this happened to you and hope the steps above will help prevent this from happening again!