Getting this on plugin loading:

Failed to call hook 'OnServerInitialized' on plugin 'Clans v0.2.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Clans.InitializeClans () [0x00017] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.OnServerInitialized () [0x0001f] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00117] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0

I have the same issue

In fact clans is just straight up not working at all. The chat commands dont work and getting multiple Null reference exceptions from it.

Failed to call hook 'Unload' on plugin 'Clans v0.2.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Clans.SaveData () [0x00000] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.Unload () [0x00000] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00238] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0

Failed to call hook 'OnUserConnected' on plugin 'Clans v0.2.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Clans.OnUserConnected (Oxide.Core.Libraries.Covalence.IPlayer player) [0x00032] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001c9] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0

Failed to call hook 'GetClanOf' on plugin 'Clans v0.2.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Clans.GetClanOf (System.String playerId) [0x00000] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.Clans.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0088e] in <99bf747509a44c80bdc612f80e7fabf5>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0

Post your clan_data.json and clas_data.json data files

Don't worry. I just removed all my config, data & lang files and reloaded Clans as a clean install and all now appears to be working.