Hi,

PaperSpigot build #1113 (and newer) doesn't work with MyWarp (b169). Prior PaperSpigot 1.12 versions, ranging from #1105 - #1112 will load without problems.

https://pastebin.com/zUUzkZPt

Another plugin also had problems starting from #1113 (but not before). I'm not sure if it's related, but this URL helped him solve it: Ste3et/FurnitureLib#27 (comment)

Looks like an error within slf4bukkit, a library MyWarp uses for logging. Its ColorMapper class relies on org.fusesource.jansi, a library that is typically bundled by CraftBukkit (and Spigot). I assume that PaperSpigot no longer bundles this library which results in the reported problem.

Since this is a problem within slf4bukkit I cannot easily fix this myself. I will however report this problem to slf4bukkit and try to get it fixed.

I (hopefully) fixed it myself. Please give the latest devBuild a try.