Player names can be duplicated in the database, preventing access

[Brianetta]

Especially when a player has been on the server while it has been both in online and offline mode, but also potentially as a result of players changing their names. Can cause players to appear to have access, but be unable to make use of it, since the database query has selected the other UUID.

UUIDs are never duplicated.

[Brianetta]

Work-around at present is to remove or rename the offending player record in the player table.