NullReferenceException at UpdateGroups

Very good plugin, works. But for some reason, one error popped into the console.

(19:30:10) | Failed to run a 15.00 timer in 'PlayerRankings v2.0.9' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PlayerRankings.UpdateGroups (BasePlayer player) [0x0000b] in <b6b49ef088654bdcad94b01503d16e33>:0
at Oxide.Plugins.PlayerRankings.<Loaded>m__0 () [0x00018] in <b6b49ef088654bdcad94b01503d16e33>:0
at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <4452f821def6406d834e4149849fe7ea>:0
Just been updated to 3.0.0
In response to pookins ():
Just been updated to 3.0.0
Updated. We will check. thank
In response to shturval ():
Very good plugin, works. But for some reason, one error popped into the console.(19:30:10) | Failed...
This is typically a configuration error, can you post your full config here?
In response to Ankawi ():
This is typically a configuration error, can you post your full config here?
At the moment I do not see an error.