We developed a bulk upload template for internal transfer - it worked perfectly only a week ago; now we try to run it again and it is no longer working. 

These are the column headers on the template:

The blocking errors are being reported by:

The errors are to do with the location IDs - for some reason it will no longer recognise them from the template although they are still assigned to the locations.

As I said, the exact same file worked perfectly last week and nothing has changed so I literally have no starting point to try to understand why it is no longer working. 

Can anyone offer some advice? Thanks!