PebbleHost Crash Example #5

Description: Exception in server tick loop

java.lang.RuntimeException: Failed to check session lock for world located at ./world, aborting. Stop the server and delete the session.lock in this world to prevent further issues.
    at net.minecraft.server.v1_8_R1.WorldNBTStorage.h(WorldNBTStorage.java:57)
    at net.minecraft.server.v1_8_R1.WorldNBTStorage.<init>(WorldNBTStorage.java:41)
    at net.minecraft.server.v1_8_R1.ServerNBTManager.<init>(SourceFile:19)
    at net.minecraft.server.v1_8_R1.MinecraftServer.a(MinecraftServer.java:249)
    at net.minecraft.server.v1_8_R1.DedicatedServer.init(DedicatedServer.java:211)
    at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:494)
    at java.lang.Thread.run(Thread.java:745)