Rejected from supply teaching from the school I did my practicum in

I did not fail my practicum and even had very positive comments from my teacher and my university tutor.

However, upon contacting that school to supply teach there, they said I did not prove my leadership in class and in the school. They did not provide any more details and suggested to do it in the school I'll do my second practicum in instead. I am in contact with other interns that were there at the same period of time and they had a positive outcome.

I wish they provided more details so I know what I did wrong (I did reply back to ask), but most importantly I would like to know if there will be consequences for my future career? Does that mean that if I go to another school, they would also reject my request? Would they ask for their reference before they take me?

Thanks a lot for your help! (Sorry about the throw away account, I'm just honestly very ashamed of this)