Player talks in chat and Rustcord tries to send to discord but fails?

Using mute command from discord also doesn't work. Discord chat to server works, player join/leave/teams/deaths all working fine. I'm loosing my mind over here. Copied from a perfectly working server and adjusted API/Discord Hooks where needed etc.

Failed to call hook 'OnPlayerChat' on plugin 'BetterChatMute v1.2.1' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.BetterChatMute+MuteInfo.IsMuted (Oxide.Core.Libraries.Covalence.IPlayer player) [0x0000b] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.BetterChatMute.UpdateMuteStatus (Oxide.Core.Libraries.Covalence.IPlayer player) [0x00000] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.BetterChatMute.HandleChat (Oxide.Core.Libraries.Covalence.IPlayer player, System.Boolean isPublicChat) [0x00008] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.BetterChatMute.OnPlayerChat (BasePlayer bplayer, System.String message, ConVar.Chat+ChatChannel chatChannel) [0x00023] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.BetterChatMute.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0008d] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <d09a1f46ca2f4432811bcfe45ad13c7b>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <cf88a28c7fb44d36890d85a78331cc9d>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <cf88a28c7fb44d36890d85a78331cc9d>:0

19:44 [Error] Failed to call hook 'API_IsMuted' on plugin 'BetterChatMute v1.2.1' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.BetterChatMute.API_IsMuted (Oxide.Core.Libraries.Covalence.IPlayer player) [0x0000b] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.BetterChatMute.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x004e8] in <5845f4fa4c544c5db4b8381ae0e2a6a8>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <d09a1f46ca2f4432811bcfe45ad13c7b>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <cf88a28c7fb44d36890d85a78331cc9d>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <cf88a28c7fb44d36890d85a78331cc9d>:0

19:44 [Error] Failed to call hook 'OnPlayerChat' on plugin 'Rustcord v2.4.2' (InvalidCastException: Null object cannot be converted to a value type.)
  at System.Convert.ChangeType (System.Object value, System.Type conversionType, System.IFormatProvider provider) [0x00029] in <fb001e01371b4adca20013e0ac763896>:0
  at System.Convert.ChangeType (System.Object value, System.Type conversionType) [0x0000c] in <fb001e01371b4adca20013e0ac763896>:0
  at Oxide.Core.Plugins.Plugin.Call[T] (System.String hook, System.Object[] args) [0x00008] in <cf88a28c7fb44d36890d85a78331cc9d>:0
  at Oxide.Plugins.Rustcord.OnPlayerChat (BasePlayer player, System.String message, ConVar.Chat+ChatChannel channel) [0x00065] in <dac0c07590e3421e9c9a99feeb39d8e0>:0
  at Oxide.Plugins.Rustcord.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x003b2] in <dac0c07590e3421e9c9a99feeb39d8e0>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <d09a1f46ca2f4432811bcfe45ad13c7b>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <cf88a28c7fb44d36890d85a78331cc9d>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <cf88a28c7fb44d36890d85a78331cc9d>:0

You may want to report the issue in the help page of Rustcord plugin

I thought about that but I am getting same error from other plugins as well, this is just an example!

Without knowing what each of those plugins are doing in those hooks, it's hard to say. These are definitely plugin-specific errors though and would need to be addressed in each plugin's support section.