What does the FMS event log say?
If you didn't save the encryption phrase then FMS would not be able to auto-host the file after it does its nightly maintenance.
Maybe I am just blind but I can't find the event log on the FM Cloud Admin Console Page. (On regular FM Server this is the first place I would have looked.)
I thought that i had clicked "Save password" perhaps i didn't but i did when I reopened this morning.
I doubt there would be anything with the AWS crashes on Tuesday that would affect it.
Thanks for the reply, I will post again tomorrow if it continues.
In the admin console:
Subscription > Subscription Center (at the bottom) > system logs (on the right towards the middle of the page)