Here's my code. . . My result for the {_online} and {_bal} is <none> I have the values and I have placeholderAPI all setup and the addons registered.
on join:
set {_online} to placeholder "%%essentials_safe_online%%"
set {_bal} to placeholder "%%vault_eco_balance_formatted%%"
while player is online:
set title of player's scoreboard to "&2&lSurvival &a&lUniverse"
set line 7 of player's scoreboard to "&2Balance &a| &f%{_bal}%"
set line 6 of player's scoreboard to "&2Team &a| &f%{team.%player%}%"
set line 5 of player's scoreboard to " "
set line 4 of player's scoreboard to "&2Playtime &a| &f%{playtime.hr.%player%}%&fhr"
set line 3 of player's scoreboard to "&2Online &a| &f%{_online}%&7/&f250"
set line 2 of player's scoreboard to " "
set line 1 of player's scoreboard to "&7mc.interzone.pro"
wait 1 tick