Hello my server is spigot 1.10 and use Gringotts and Essentials

/vault-convert EssentialsEconomy Gringotts

{\rtf1\ansi\ansicpg1252\deff0\deflang11274{\fonttbl{\f0\fnil\fcharset0 Arial;}} {\colortbl ;\red0\green0\blue255;\red255\green0\blue0;} \viewkind4\uc1\pard\cf1\fs18 10:06:48 p. m. [INFO] CubyMaster issued server command: /vault-convert EssentialsEconomy Gringotts\par 10:06:48 p. m. [SEVERE] null\par 10:06:48 p. m. org.bukkit.command.CommandException: Unhandled exception executing command 'vault-convert' in plugin Vault v1.5.6-b49\par \cf2 10:06:48 p. m. \tab at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:646) ~[spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.PlayerConnection.handleCommand(PlayerConnection.java:1351) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.java:1186) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par \cf1 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par \cf2 10:06:48 p. m. \tab at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_66]\par 10:06:48 p. m. \tab at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_66]\par \cf1 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.SystemUtils.a(SourceFile:45) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par \cf2 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:733) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:672) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:571) [spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par 10:06:48 p. m. \tab at java.lang.Thread.run(Unknown Source) [?:1.8.0_66]\par 10:06:48 p. m. Caused by: java.lang.NoSuchFieldError: accountHolderFactory\par 10:06:48 p. m. \tab at net.milkbowl.vault.economy.plugins.Economy_Gringotts.hasAccount(Economy_Gringotts.java:125) ~[?:?]\par 10:06:48 p. m. \tab at net.milkbowl.vault.economy.AbstractEconomy.hasAccount(AbstractEconomy.java:10) ~[?:?]\par 10:06:48 p. m. \tab at net.milkbowl.vault.Vault.convertCommand(Vault.java:461) ~[?:?]\par 10:06:48 p. m. \tab at net.milkbowl.vault.Vault.onCommand(Vault.java:412) ~[?:?]\par 10:06:48 p. m. \tab at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.10.jar:git-Spigot-c55900f-9856d8a]\par \cf1 10:06:48 p. m. \tab ... 15 more}

Looks like the version of Gringotts you are using may not be compatible with the Vault adapter. Your report is extremely difficult to read as you tried to paste into github. Please utilize a gist or something like pastebin for stack traces.