I was told to go here to explain the issue and that it is likely a 1.16.1 issue. Whenever the command /show is used in order to attempt to get players to appear on the map I get an error.

31.07 13:36:18 [Server] ERROR null
31.07 13:36:18 [Server] INFO org.bukkit.command.CommandException: Unhandled exception executing command 'dynmap' in plugin dynmap v3.0-SNAPSHOT-338
31.07 13:36:18 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at org.bukkit.craftbukkit.v1_16_R1.CraftServer.dispatchCommand(CraftServer.java:794) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.PlayerConnection.handleCommand(PlayerConnection.java:1912) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.PlayerConnection.a(PlayerConnection.java:1723) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.PacketPlayInChat.a(PacketPlayInChat.java:47) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.PlayerConnectionUtils.lambda$ensureMainThread$1(PlayerConnectionUtils.java:23) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.TickTask.run(SourceFile:18) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.MinecraftServer.aZ(MinecraftServer.java:1137) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.MinecraftServer.executeNext(MinecraftServer.java:1130) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.IAsyncTaskHandler.executeAll(IAsyncTaskHandler.java:95) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.MinecraftServer.a(MinecraftServer.java:1260) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.MinecraftServer.v(MinecraftServer.java:1001) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at net.minecraft.server.v1_16_R1.MinecraftServer.lambda$a$0(MinecraftServer.java:177) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_242]
31.07 13:36:18 [Server] INFO Caused by: java.lang.NullPointerException
31.07 13:36:18 [Server] INFO at org.dynmap.bukkit.DynmapPlugin$BukkitPlayer.(DynmapPlugin.java:606) ~[?:?]
31.07 13:36:18 [Server] INFO at org.dynmap.bukkit.DynmapPlugin.onCommand(DynmapPlugin.java:1028) ~[?:?]
31.07 13:36:18 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[patched_1.16.1.jar:git-Paper-129]
31.07 13:36:18 [Server] INFO ... 18 more

Assuming this is fixed in a later release or otherwise no longer relevant- please open a new issue if this persists.

you are not on the lastest version of dynmap. Please use the latest version found here and let me know if the issue persists

I have updated to the latest version of dynmap. What can I do next in order to make player heads appear on the map?

can you pastebin your configuration.txt?

Do you see player locations on the map but not heads? can you send a screenshot of this as well

EDIT: remove pastebin link due to password
Here it is.

Player heads do at their location but the map will direct if you click them on the right.

Don't forget to remove your mysql passwords before you pastebin configs 😉 I removed the link but you don't want that falling in the wrong hands

in this section of the config

  # Note: this component is needed for the dmarker commands, and for the Marker API to be available to other plugins
  - class: org.dynmap.MarkersComponent
    type: mysql
    showlabel: false
    enablesigns: false

change this line to
type: markers

Alright it has been changed! Ill let you know if it worked! Also thanks for that haha

At least I can see the spawn marker, but I do get this error message.

did you do a /dynmap reload or a full server restart

server restart

someone else is having that exact same error on the discord for a completely unrelated issue let me do some more digging

any ideas?