Your plugin started to give an error in one of the plugins I bought,
I wrote to the developer of this plugin and he told me that the error was in your plugin CopyPaste

XDQuest was compiled successfully in 2045ms
Loaded plugin XDQuest v7.5.1 by DezLife
SqliteException: Could not finalize SQL statement: database disk image is malformed (11)
Exception while calling NextTick callback (SqliteException: Could not finalize SQL statement: database disk image is malformed (779))
  at Facepunch.Sqlite.Database.Finalize (System.IntPtr stmHandle) [0x00032] in <eebd84cc055944e3b9d7dd5292f98ce0>:0 
  at Facepunch.Sqlite.Database.FinalizeOrReset (System.IntPtr stmHandle, System.Boolean finalize) [0x00003] in <eebd84cc055944e3b9d7dd5292f98ce0>:0 
  at Facepunch.Sqlite.Database.ExecuteQuery (System.IntPtr stmHandle, System.Boolean finalize) [0x00022] in <eebd84cc055944e3b9d7dd5292f98ce0>:0 
  at Facepunch.Sqlite.Database.Execute[T1,T2,T3,T4,T5] (System.String query, T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5) [0x00033] in <eebd84cc055944e3b9d7dd5292f98ce0>:0 
  at FileStorage.Store (System.Byte[] data, FileStorage+Type type, NetworkableId entityID, System.UInt32 numID) [0x0001d] in <85a0464fb6274df7a9147a488c9061a6>:0 
  at Oxide.Plugins.CopyPaste.FixSignage (Signage sign, System.Byte[] imageBytes, System.Int32 index) [0x00076] in <eeec479dd5e14e6083b60f4e4c148323>:0 
  at Oxide.Plugins.CopyPaste.PasteLoop (Oxide.Plugins.CopyPaste+PasteData pasteData) [0x00d30] in <eeec479dd5e14e6083b60f4e4c148323>:0 
  at Oxide.Plugins.CopyPaste+<>c__DisplayClass44_0.<PasteLoop>b__0 () [0x00000] in <eeec479dd5e14e6083b60f4e4c148323>:0 
  at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <b6d06fce9e044af4a6ddc8d724bd3b0b>:0

Your plugin itself works fine,

but an error suddenly appeared in one of the plugins, and this error refers to your plugin as another developer told me!

This error is not caused by Copy Paste, it's within game methods used by Copy Paste instead. This means one of your db files in the server folder was corrupted and you need to delete it, likely sv.files one.