".....only approved for commercial or portfolio loans."

Chris, at this moment you should thank your lucky stars. You are going to learn more about the 21 ways to finance a real estate deal than 90% of your peers.

As you have noted, there is a mismatch regarding buyer capability and zoning classification of the real estate. Securing commercial property without a history of business success is costly. Everyone knows 80% of business's fail and 4 of the first 5 attempts of a business aspiree fail.

Such historic evidence is undeniable. So.....

What collateral does the buyer have that anyone cares about? This goes in the direction of portfolio lending.

What do the LOCAL banks with unrecognizable names advise? I'm serious, make an appointment, give an overview, listen carefully, then followup with client appointment if potential exists. You want to do this to establish YOURSELF as a professional in this business space. You will learn a LOT and this will prove a real advantage when 'newbie' is removed from your introduction. Don't stop at one bank. Get out there.

You can choose to visit with big banks but you need to hear what they are NOT saying to know what you must do. A newbie is unlikely to have those ears. They WANT to tell you but can not. So be creative with your questions.

Finally, get out your sleuth snooper and find brokers who are not members of the board. These brokers exist in the 'wild, wild, west of real estate," because they have VISION. Call them up and say, 'Houston we have a problem."

But those of us who have been around for more than a week must wonder, "Where is your broker?" The truth is we know but are too polite to tell you.

Check with your local bank or local commercial mortgage broker. This is normally a local play including the buyer having a banking relationship! 

You have to run it by each bank seperately. Can't believe the LA didn't try & find a lender willing to do it. That's what I would have done.

I'll assume that the stables & arena are providing income.

Your trusted local mortgage loan officer should be able to give you some suggestions.

Good luck! You will not be able to get "normal" financing on a special purpose property. You are basically looking at a business loan secured by real estate. Banks consider that to be high risk. There may be a lender who will do this deal but it will take a large down payment and an interest rate higher than a residential real estate loan.

You didn't mention whether this was an income-producing property, although I'm assuming it is. This is where you need to get your buyer with a commercial lender. There are likely many scenarios but if it's a commercial deal, and it's an income-producing property, the seller's numbers are going to be important as well as the business plan of the borrower.
See my response to your comment on Lyn's answer for more.

I've only sold equestrian properties that had a residential structure on the property as well as horse & stables and a residential mortgage was used.

Ask your preferred lender. Perhaps he/she has a recommendation for you. 

Good luck!

I beleive it's going to vary by lender. I had a similiar property here sail through as a residential loan.

You should ask your local residential lenders for referrals to a commercial lender.

Check with your local Lender, they no doubt have a referral for you.  A

No, I wish I knew.

I am not a banker but I tell my clients to be ready to give info and hurry up and wait

it looks like you have plenty of guidance here....

I'd defer to Candice A. Donofrio for commercial and John Meussner for loans.

A new agent is out of their expertise, GET HELP NOW.

Find an experienced agent to team up with on this, or refer it RIGHT AWAY.

No, would make some local calls to commercial agents.

Hope a lender can reach out to you from AR

Almost certainly going to be an Ag loan. Start with Farmer Mac to see if they will do it: https://www.farmermac.com

I could not say it any better than Annette Lawrence , Palm Harbor, FL 727-420-4041 - 

I don't really understand why it must have a commercial loan unless the buyer is planning on running it as a business.

No.

No. 

How many acres is the property? Does it cash flow? What is the buyer's background and experience with owning this type of property? How is the buyer's credit? What amount of down payment will he have? Does he have good resources/reserves?  You need the answers to those questions before you start approaching lenders looking for financing and you may be best off working with a good mortgage broker. Unique properties require unique financing and mortgage brokers typically have access to a wide range of those types of programs. Former LO and mortgage broker here who did some commercial loans back in the day.