Unable to change configuration via CSV method for devices uploaded to Zero Touch customer portal

Hello,

Until earlier today, I was able to upload existing devices via .csv with a view to changing their configurations. This is because our resellers are unable to choose which configuration to use upon upload (we have two for different types of devices).

Despite simply trying to change configurations for existing devices, I'm getting the error "You don't have permission to add devices for the customer". As I mentioned, this was working earlier today, all of a sudden I'm now unable to do this for devices that already exist in the portal.

I'm using the .csv template provided with "modemtype", "modemid" and "profileid" filled out, which had been working. For now I'm having to do this manually for devices. Any help would be much appreciated.