[10:08:31 WARN]: java.lang.NoSuchFieldException: sign
[10:08:31 WARN]:        at java.lang.Class.getDeclaredField(Class.java:2070)
[10:08:31 WARN]:        at pro.lvlup.mcshop.nms.Reflections.getDeclaredField(Reflections.java:152)
[10:08:31 WARN]:        at pro.lvlup.mcshop.utils.Utils.openGui(Utils.java:87)
[10:08:31 WARN]:        at pro.lvlup.mcshop.listeners.InventoryListener$1.run(InventoryListener.java:60)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:71)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:52)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[10:08:31 WARN]:        at java.lang.Thread.run(Thread.java:748)
[10:08:31 WARN]: java.lang.NullPointerException
[10:08:31 WARN]:        at pro.lvlup.mcshop.nms.Reflections.setDeclaredField(Reflections.java:174)
[10:08:31 WARN]:        at pro.lvlup.mcshop.utils.Utils.openGui(Utils.java:88)
[10:08:31 WARN]:        at pro.lvlup.mcshop.listeners.InventoryListener$1.run(InventoryListener.java:60)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:71)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:52)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[10:08:31 WARN]:        at java.lang.Thread.run(Thread.java:748)
[10:08:31 WARN]: java.lang.NullPointerException
[10:08:31 WARN]:        at pro.lvlup.mcshop.nms.Reflections.setDeclaredField(Reflections.java:174)
[10:08:31 WARN]:        at pro.lvlup.mcshop.utils.Utils.openGui(Utils.java:89)
[10:08:31 WARN]:        at pro.lvlup.mcshop.listeners.InventoryListener$1.run(InventoryListener.java:60)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:71)
[10:08:31 WARN]:        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:52)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[10:08:31 WARN]:        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[10:08:31 WARN]:        at java.lang.Thread.run(Thread.java:748)