Interesting info ! ...skype is supposed to use "global hotkeys"
Skype uses global hotkeys, which do not require the application('s window) to have focus (and are enabled by default).
and of course they have REMOVED the ability to change those commands by the user..so mute is stuck at Left Ctrl M
very odd that for me it seems that ONLY when DCS is running, skype ignore these global hotkeys.
That certainly did NOT used to be the case...so something has clearly changed
even stranger that Discord shortcuts dont work but Ctrl M does in your case...now thats weird !