It's due to an injury he had in his last fight. It's a "medical suspension" - the commission has a rule that injured boxers are not permitted to fight.
It doesn't mean anything. New York automatically suspends every fighter after they have fight in their state. It says the same thing for Wilder.
There was one too many Loma threads started here and NYSAC sprang into action in response. Just by asking this question you've pushed his next fight back 3 months