1x ...eElvUI_WindTools/Modules/Social/ChatText.lua:1986: wrong number of arguments to 'insert'
[string "=[C]"]: ?
[string "@ElvUI_WindTools/Modules/Social/ChatText.lua"]:1986: in function `SendAchivementMessage'
[string "@ElvUI_WindTools/Modules/Social/ChatText.lua"]:2075: in function <...eElvUI_WindTools/Modules/Social/ChatText.lua:2074>

Locals:
(*temporary) =

Is it the full error you got from game?

The message after Locals: may very helpful in debugging.