If a UUID of a region is already listed on the map (also counts for duplicate names and/or coordinates), it cannot boot, and will simply crash the simulator at startup. UUID's are required to be unique.
Try the stuff below to get is resolved :
1. Shutdown all regions, and make sure they have a unique name / UUID / location on map and UDP port in your region.ini files.
2. If you run multiple simulators, make sure the http listener port of each sim is set to a unique TCP port in opensim.ini
3. If all is set correct, login to your account on the Osgrid website, click my profile, and purge all regions from your account.
4. Optional : Clear your viewer cache (prevents you from looking at cached stuff on the map).
5. Start your regions, they should re-register on the map without any issue.
6. Test if your problems are resolved.