WorldGuard version:
6.2.2
Platform version:
Spigot 1.12.2

When i Try to add a player of my server who is disconnect and do not have a mojang account because my server allow offline mode, i can't add it.

To Reproduce

1. Set online mode to false and join with a name that is not used by any mojang account
2. Disconnect
3. Execute /rg addmember yourregion -w world playername
4. The message is: Failed to add new members: Unable to resolve the names "playername"

Expected behavior
Possibility to add this user !

old versions and offline mode are unsupported.

Seriously...