Marriot Bonvoy not transferring miles to American

I currently have 70,000 points I want to transfer to American Airlines for a rate of around 23,000+ miles. I'm aware that United will give me more with the bonus 10,000 miles but due to a certain travel itinerary it makes sense to use American.

Unfortunately, every time I go to transfer my points and hit "continue" it times out. I tried United and it sent me to the next page confirming if I wanted to transfer to them.

Does anyone know why it won't let me transfer to American Airlines? I tried my phone, laptop and work computer and all got the same result.