I can try, if it happens again at RO. Otherwise i wont be doing Breeding for awhile

So i keep trying to breed one of my SD stallions, with a SD public breeding mare. Neither have breeding reqs and yet every time i try to breed them i get a red message that says

I had this too, i was trying to breed a EEE mare to a WWW stud, the stud had no requirements at all.

Can you guys please provide links to the horses when this happens?