I need help with my code for my screboard

[Appa_Yip]

I keep on getting 

Line 7: (Tab.sk)

Can't understand this expression: bl

Line: set loop-player's tab list header to "{@Header}"

Code:

options:
    Header: Welcome To &3&lAppaBending.minehut.gg%bl%&7OnlineP Players: &a%{online}% %nl%
    Footer: %nl%&b/discord

every second:
    loop all players:
        set loop-player's tab list header to "{@Header}"
        set loop-player's tab list footer to "{@Footer}"
        set {Online} to number of all players
        stop
command /discord:
    cooldown: 10 seconds
    cooldown message: Please wait 5 seconds before using this command again.
    trigger:
        send "discord.gg/" to player