Thanks for the link, didn’t find anything for my specific problem but did find a bunch of other good stuff.
My problem isn’t a problem really even if my links in email open in Firefox they still open, I can copy and paste to eM.
In PM, click > Tools / Options / Advanced / General tab / and at the bottom, click the bar to make PM your default browser.
Am guessing you never specified a default browser after making the switch to PM, and that should fix your problem.
If not, there's prolly a similar option that needs checked in your email app to point it to PM instead of FF.
Is Pale Moon your default browser?
Similar question:
Check that firefox is not your default browser in settings.