the line where error pops out is the line where I changed the argument for set_task on Satan's suggestion.
When I pass idd (an array) to kac_exists function thru set_task, I don't get any errors while compilation but only first person to connect is checked for valid token and rest are simply ignored.
I want my plugin to wait for 60 seconds after a client has connected and then check if the token is valid or not in DB. This task should be set for all people who connect but doesnt happen so.