The same here…
I wouldn’t do any changes on the site for a while.
This error could be caused by changements (upgrades on wix side).
Just wait for 1-2-days and see if everything works again.
If not, then contact wix.
Sudden comming ERRORs, without changing CODE on site is a WIX-sided error in most of the cases.
https://www.wix.com/corvid/forum/community-discussion/strange-and-unexpected-collapse-problem