any ideas ?

(13:33:12) | Failed to call hook 'OnServerInitialized' on plugin 'CustomAutoKits v1.2.0' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.CustomAutoKits.IsKit (System.String kitname) [0x00028] in <bfef6778907a4a27847e75c39e25008e>:0
at Oxide.Plugins.CustomAutoKits.OnServerInitialized () [0x00060] in <bfef6778907a4a27847e75c39e25008e>:0
at Oxide.Plugins.CustomAutoKits.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001cd] in <bfef6778907a4a27847e75c39e25008e>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <98321e516fc1420ea57d4d2088213a59>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <ac41dd3599754d448b8c218b34645820>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <ac41dd3599754d448b8c218b34645820>:0
(13:33:12) | Loaded plugin Custom Auto Kits v1.2.0 by Absolut/Arainrr

There cannot be an empty value in the configuration file..

i have deleted the config file and let it create the default with the same result

Please use this kit plugin  https://umod.org/plugins/rust-kits
Maybe the "isKit" function is missing from your kits