Upload file: Getting 'you can only upload following files error

I am getting the same problem with a couple of my forms.  Users have been uploading images fine until yesterday and then they started getting the error: You can only upload following files:

It seems that it is an intermittent, but I have just tested one of the forms myself and got the same error.  

Can someone help please as we have people trying to upload files for a deadline tonight.

Thanks!

It seems like this is a duplicate thread, I see that you've also opened your own thread. Please follow up there: https://www.jotform.com/answers/969436-Error-You-can-only-upload-following-files-#0