I've just checked my "AdSense Mediation" button and it's all fine now. Thank you a lot for all your help. :-)
Regarding AdSense ad code; I don't really have ad locations (as in, specific areas where I added code for an ad to show up). I'm using "Auto ads" (so Google automatically show ads in all the best places for me).
What I meant by "AdSense code" is the code snippet one needs to add in between the <head></head> tags of the site. Can I safely remove it (it might make my site a few milliseconds faster not having to load it up)?
Thank you again and wish you a nice weekend!