Bug Report

Type /ver NametagEdit and post the output.
Nametagedit 4.1.7

What version of Bukkit/Spigot/PaperSpigot are you using? Type /ver
server is running CraftBukkit version git-Spigot-db6de12-18fbb24 (MC: 1.8.8) (Implementing API version 1.8.8-R0.1-SNAPSHOT)

What plugins are you using? Type /plugins
Vault, ProtocolLib, PlaceholderAPI, EssentialsX, ViaVersion, WorldGuard, Worldedit & PEX

Please explain your issue. How do you trigger it?
When i join my server , it generates an exception.
Also, If i try to add prefix on myself , it do not work + there are errors in server console.

Are there any errors in the console? Please use: https://pastebin.com

https://pastebin.com/DwR04r76

[06:37:40 WARN]: [MVdWPlaceholderAPI] There is no MVdW placeholder plugin installed!
[06:37:40 WARN]: [MVdWPlaceholderAPI] Put on of Maximvdw's premium placeholder plugins in the server!

Edit: It appears when the Nametag was formatted it returned a null string. I will incorporate a fix to gracefully notify you of this rather than erroring out.