I don't think a lender can decided not to fund and not provide a reason. Not sure about Ohio law, but it seems to me that with all the new(ish) Truth in Lending requirements, and the advent of the CFPB, that a reason would be supplied. I counsel my sellers to require a pre-approval (not a pre-qualification, a pre-approval) letter with an offer.
Did the lender ever issue a written loan commitment? There is often contract language that requires a written loan commitment. Your agent should be all over this, both because it's his job, and because he doesn't get paid until closing. If he hasn't counseled you on your options, you need a better agent.
Barring recourse against the lender, check with your agent to see if you can keep the buyer's earnest money. In Florida, you would have recourse if this actually occurred within 7 days of closing. The earnest money wouldn't completely compensate you if you lose the sale, but at least you could then consider putting additional earnest money towards the house you are buying, which would help convince that seller that you are serious. In the alternative, you could use the money to just "buy" an extension of the closing date for the Florida house. Whatever you do, be truthful with the seller of the house you are buying.