I can verify my discord account, it's fine, but when I try to unpair my account with /dc leave after verification, I get an error.
When I did o.reload DiscordCore, my account was unlinked, but I saw that my discord authority in the game was still stopped.

I use DiscordCore, DiscordGroups and DiscordRoles plugins

[Discord Core] Lang Key 'Linking.Chat.Unlinked' threw exception
:System.FormatException: Input string was not in a correct format.
  at System.Text.StringBuilder.AppendFormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x0005c] in :0 
  at System.String.FormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x00023] in :0 
  at System.String.Format (System.String format, System.Object[] args) [0x00020] in :0 
  at Oxide.Plugins.DiscordCore.Lang (System.String key, Oxide.Core.Libraries.Covalence.IPlayer player, System.Object[] args) [0x0001c] in :0 
Failed to call hook 'DiscordCoreChatCommand' on plugin 'DiscordCore v2.1.2' (FormatException: Input string was not in a correct format.)
  at System.Text.StringBuilder.AppendFormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x0005c] in :0 
  at System.String.FormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x00023] in :0 
  at System.String.Format (System.String format, System.Object[] args) [0x00020] in :0 
  at Oxide.Plugins.DiscordCore.Lang (System.String key, Oxide.Core.Libraries.Covalence.IPlayer player, System.Object[] args) [0x00041] in :0 
  at Oxide.Plugins.DiscordCore.Chat (Oxide.Core.Libraries.Covalence.IPlayer player, System.String key, System.Object[] args) [0x0000b] in :0 
  at Oxide.Plugins.DiscordCore.HandleLeave (Oxide.Core.Libraries.Covalence.IPlayer player, Oxide.Ext.Discord.Entities.Users.DiscordUser user, System.Boolean backup, System.Boolean message) [0x00064] in :0 
  at Oxide.Plugins.DiscordCore.DiscordCoreChatCommand (Oxide.Core.Libraries.Covalence.IPlayer player, System.String cmd, System.String[] args) [0x00101] in :0 
  at Oxide.Plugins.DiscordCore.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00520] in :0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in :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 

Looks like your lang for key Linking.Chat.Unlinked is invalid. You would need to fix that on your end.

Thanks, I was able to solve the problem. It works fine now, but the only problem is when I translate to different languages, the Discord bot works in English and does not respond in other languages.

Not everything can be translated due to not having the user language when using commands in discord. This will be solved once this plugin can move to discord slash commands.