I encountered the same problem today and found a workaround/solution.
- I logged out and logged back in Firefox
- I looked at the 'Document type' drop down list and it now has 'Passport or Other Primary ID Document'. Previously it didn't had it.
- I uploaded my passport in this new 'Passport or Other Primary ID Document' category
- I deleted my previous upload of my passport under a different category
- Still the Submit button was greyed out, so I filled and signed the consent form once again.
- Now, the Submit button was enabled and I was able to submit the application.
So, for users who have uploaded their passport in the old, not so exact, ID categories, they need to upload it in 'Passport or Other Primary ID Document' and the key is to sign the consent form again and then the submit option will be enabled.
