Does this help?
https://i.imgur.com/wMvFsqb.jpg

can you confirm you dont have mapmarkers ?

Yes. As you see in the screenshots the heli is at the dome but the map won't show it. The marker in the left upper corner is an airdrop.
The plugin is definitely installed and I have a config too.https://i.imgur.com/yikO6ss.jpg https://i.imgur.com/GjCXawB.jpg

04:10 [Error] Failed to initialize plugin 'MapMyPatrol v0.0.5' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.MapMyPatrol.Loaded () [0x0004f] in <f6d27d22ef6543aab0319719431f66ed>:0
at Oxide.Plugins.MapMyPatrol.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x000bf] in <f6d27d22ef6543aab0319719431f66ed>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0
at Oxide.Plugins.CSharpPlugin.HandleAddedToManager (Oxide.Core.Plugins.PluginManager manager) [0x0006e] in <9affce1cd15c4ec183941adef8db1722>:0
I just noticed this error loaded fine granted permission just fine 

So, what does this say?
There is an error I guess.
What is it?
Is it the problem I have?
Can it be fixed?

Merged post

I deinstalled the plugin and installed it again but no change. Still no marker on the map and/or HUD.
Could it be a problem with the Heli Control Plugin which I also have?

Merged post

If I set the permission manually in the console with oxide.grant group admin mapmypatrol.hud it says "Permission 'mapmypatrol.hud' doesn't exist".