Download failed with status code 403

Global Mapper is a product independent from OpenStreetMap. If you have paid any money to Global Mapper for your "single user license" then OpenStreetMap has not received any of that money. OpenStreetMap's free tile servers are funded through donations, and OpenStreetMap reserves the right to limit access to these free resources at any time. Global Mapper should have made you aware of this, and that any use of OpenStreetMap's free resources is governed by the Tile Usage Policy. Among other things, this policy says that:

• Heavy use (e.g. distributing an app that uses tiles from openstreetmap.org) is forbidden without prior permission
• Bulk downloading is strongly discouraged. ... In particular, downloading an area of over 250 tiles at zoom level 13 or higher for offline or later usage is forbidden

It is likely that you have used Global Mapper in a way that has violated these rules and therefore you have been blocked from OpenStreetMap. I suggest that you contact Global Mapper support about this.