Can a landlord deny a family of having two service animals

I recently moved into an apartment with my 4 year old son. I have a registered service dog that I have had for 10 years for my disability. My son’s therapist and doctor both recommended an ESA for him about 5 months ago. I signed my lease and had to get updated paperwork for both animals because the landlord refused the original paperwork on them saying it was outdated. When I turned in the updated paperwork I was told that she would not approve both animals because she didn’t feel comfortable having 2 dogs in one apartment with a no pet policy. Is this legal for her to do? 

I don't think this is legal, but please check with HUD Fair Housing. They have a Housing Discrimination Hotline where you can ask these kinds of questions and they will help you through. That number is 1-800-669-9777.
2 people have 2 animals for 2 different purposes. The landlord is, in effect, denying one of you a medical device. Please follow up. Landlords like that give the rest of us a bad name.