An exception was thrown while executing task 72, unable to call the method org.bukkit.Server.isStopping().

[1343008086]

Required Information

• FAVS Version Number (/version IllegalStack):2.9.9
• Spigot/Paper Version Number (/version):Spigot 1.16.5
• Output of /version:version 1.16.5-69069a9c (MC: 1.16.5) (Implementing API version 1.16.5-R0.1-SNAPSHOT, Forge version 36.2.39)

Describe the bug

[10:55:54] [Craft Scheduler Thread - 31/WARN] [main.java.me.dniym.IllegalStack]: [IllegalStack] Plugin IllegalStack v2.9.9 generated an exception while executing task 72
java.lang.NoSuchMethodError: org.bukkit.Server.isStopping()Z
	at main.java.me.dniym.timers.fTimer.run(fTimer.java:122) ~[?:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:81) ~[forge:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [forge:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
	at java.lang.Thread.run(Thread.java:750) [?:?]
[10:55:54] [Craft Scheduler Thread - 29/WARN] [main.java.me.dniym.IllegalStack]: [IllegalStack] Plugin IllegalStack v2.9.9 generated an exception while executing task 72
java.lang.NoSuchMethodError: org.bukkit.Server.isStopping()Z
	at main.java.me.dniym.timers.fTimer.run(fTimer.java:122) ~[?:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:81) ~[forge:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [forge:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
	at java.lang.Thread.run(Thread.java:750) [?:?]
[10:55:55] [Craft Scheduler Thread - 28/WARN] [main.java.me.dniym.IllegalStack]: [IllegalStack] Plugin IllegalStack v2.9.9 generated an exception while executing task 72
java.lang.NoSuchMethodError: org.bukkit.Server.isStopping()Z
	at main.java.me.dniym.timers.fTimer.run(fTimer.java:122) ~[?:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:81) ~[forge:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [forge:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
	at java.lang.Thread.run(Thread.java:750) [?:?]
[10:55:55] [Craft Scheduler Thread - 28/WARN] [main.java.me.dniym.IllegalStack]: [IllegalStack] Plugin IllegalStack v2.9.9 generated an exception while executing task 72
java.lang.NoSuchMethodError: org.bukkit.Server.isStopping()Z
	at main.java.me.dniym.timers.fTimer.run(fTimer.java:122) ~[?:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:81) ~[forge:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [forge:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
	at java.lang.Thread.run(Thread.java:750) [?:?]
[10:55:56] [Craft Scheduler Thread - 33/WARN] [main.java.me.dniym.IllegalStack]: [IllegalStack] Plugin IllegalStack v2.9.9 generated an exception while executing task 72
java.lang.NoSuchMethodError: org.bukkit.Server.isStopping()Z
	at main.java.me.dniym.timers.fTimer.run(fTimer.java:122) ~[?:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:81) ~[forge:?]
	at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [forge:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
	at java.lang.Thread.run(Thread.java:750) [?:?]

To Reproduce
Steps to reproduce the behavior:

1.Install the plugin and run the server.
2.Wait until all plugins are loaded.
3.Continuously refresh the occurrence of this error.

Plugins being used on the server

Checklist:

• [] I included all information required in the sections above
• [] I made sure there are no duplicates of this report (Use Search)
• [] I made sure I am using an up-to-date version of IllegalStack
• [] I made sure the bug/error is not caused by any other plugin