1. Open the people floater and the minimap. Make sure the world map is not open.

2. If any map textures are grey jump to step 4

3. Teleport around until a map texture in the people floater and minimap remains grey

4. Open the World Map, it will fetch the missing texture and the grey textures will be replaced with the map tile.

https://secondlife.canny.io/admin/board/bug-reports/p/netmap-fails-to-fetch-some-map-textures