How do i fix this?

Uhh. I’m sorry my crystal ball broke. I’m afraid we’ll need more info to help you solve your issue.

Things like server platform (like Bukkit), versions (of LP at minimum) and error logs.

I'm Using BungeeCord And All Servers are Spigot 1.12.2

I don't see anything in the error logs?

You must be seeing an error somewhere. What’s said error? Where does it appear, what’s the error message? What did you do that triggered that error.

/lp networksync How do you setup the messaging service?

Click the big fat wiki button on the top of this page and then click “Network Installation” on the right. There’s your tutorial.