Since many publishers sell rights to publish editions in other territories, a publisher may not have permission to approve your request if you are located in a non-preferred region.
When you request a title outside of your region, the publisher will see that request flagged as "out-of-region." Out-of-region requests are much less likely to be approved.
If you are working as a rights agent, or international buyer, we highly recommend asking your trade contact to auto-approve you for all future requests. You can browse by titles you are auto-approved for, and this is the fastest way to have regular access to titles from key publishers.
In many cases NetGalley will have multiple editions available for request.