AAC Error

[01:26:39 INFO]: LiLtUwU lost connection: Disconnected
[01:28:49 INFO]: UUID of player Lunchbloxx is 838d512e-30ec-4acd-b848-58893faeee30
[01:28:49 WARN]: [AAC5] Unresolved version for Lunchbloxx check your ViaVersion/ProtocolSupport build
[01:28:49 WARN]: [AAC5] Task #10 for AAC5 v5.1.0 generated an exception
java.lang.NullPointerException: null
        at me.konsolas.aac.t.hashCode(t.java:27) ~[?:?]
        at java.util.HashMap.hash(HashMap.java:339) ~[?:?]
        at java.util.HashMap.get(HashMap.java:552) ~[?:?]
        at me.konsolas.aac.d_.a(d_.java:20) ~[?:?]
        at me.konsolas.aac.O.<init>(O.java:151) ~[?:?]
        at me.konsolas.aac.ab.a(ab.java:258) ~[?:?]
        at me.konsolas.aac.ab.<init>(ab.java:6) ~[?:?]
        at me.konsolas.aac.ad.<init>(ad.java:71) ~[?:?]
        at me.konsolas.aac.dO.a(dO.java:131) ~[?:?]
        at me.konsolas.aac.dO.a(dO.java:36) ~[?:?]
        at me.konsolas.aac.timings.CheckTask.run(CheckTask.java:2) ~[?:?]
        at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:100) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:468) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at net.minecraft.server.v1_16_R3.MinecraftServer.b(MinecraftServer.java:1489) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at net.minecraft.server.v1_16_R3.DedicatedServer.b(DedicatedServer.java:437) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at net.minecraft.server.v1_16_R3.MinecraftServer.a(MinecraftServer.java:1402) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1134) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:292) ~[patched_1.16.5.jar:git-Tuinity-"901ac35"]
        at java.lang.Thread.run(Thread.java:834) [?:?]