Hi @NicolaORourke ...
When you edit your assignment details, one of the options is "External Tool". This typically means a third-party integration is being used inside of Canvas. Some examples might be Turnitin, Kaltura, McGraw-Hill, etc. Under the "External Tool" option, there's usually a URL that is displayed, and that would give you an idea of what external tool is being used. Also, if you exit out of the editing screen for the assignment and return to what a student would see, you should see whatever external tool interface is being used for that assignment.
When I have an external tool selected, I can still change the number of attempts from "Unlimited" to "Limited". However, if you are using something like Turnitin, I *think** the interface for Turnitin has its own settings...including if resubmissions are allowed. So, the setting on Canvas may *not* be the same as what it might be in something like Turnitin.
I hope this helps a bit. Let folks in the Community know if you have any questions...thanks!
