We are seeing users report this issue too. Only thing I have found is that it could be ISP related - tested all other settings on same Marketplace product item and only one user gets the error.
May need to login with the same agol user from another place.
I’m so sorry you are having trouble.
We recently made some changes to our site. The homepage is loading for me
Will you please send an email to email@example.com with the URL you are trying to access?
Thanks in advance.
Our user Ricky_NFS just tried again and still gets the 504. It's the trial button on the Prism app that gets the timeout. I cannot give the proper link because I own Prism and can't see the trial button.