See these threads;

https://forum.mendix.com/link/questions/111800

https://forum.mendix.com/link/questions/111799 

And Mendix’ statement: 

https://status.mendix.com/incidents/8j5043my610c 

and if you are already on 9.9.0, see https://docs.mendix.com/releasenotes/studio-pro/9.9