Hi @awade ,
I'm so sorry that you are dealing with this. This sounds like an issue on our back end, but just like you said there were no reports of service outages yesterday. I tested this in my own tenant and was able to register an application without a problem, so maybe the outage is resolved by now. Were you able to test in a different browser and see if you could get it to work?
I reported this to the product team and will get back to you with their response. Meanwhile, if you are still having this issue, please feel free to send me an email (left in the private comment below), and I will gladly open a free support case for you to get this resolved.
Thank you for your patience!
Marilee