I have a neutered male rabbit that was fully potty trained, I adopted a female 5 month old rabbit and now our male has reverted to potty all over the floor along with the female. What do I do?

Who trained the male?

Are the male and female housed together?

If so, it's very likely that because the female isn't potty trained, and she's peeing and pooing wherever she wants to in his home, he's regressed to doing the same.

My advice would be to separate them for now and work on potty training the female, and retrain the male. They're fairly easy to potty train, they don't like to sleep in their own mess and will normally find a corner that is theirs to use as a potty. Simply find the corner they both like to use, put a potty in it with rabbit friendly litter, then add a few pellets of their own poop and wait. If they suddenly use a different corner, get a second litter box and place it in that corner. Sooner or later they'll run out of options and they'll use the potty because it's in the corner, and that's where they prefer to go.

I'd love to see pictures. I have 3 rabbits, used to have 4, all spayed or neutered. They're wonderful pets.