Hi @mayhew3,
I’m glad to hear you were able to isolate the issue. I’m sorry to hear it was so difficult to track down. I agree with you that it would be helpful to have more detailed errors than Login required. I am not sure what is causing the behavior related to the cross-site tracking setting. I will ask about this.
Also, it’d be great to get this feedback passed on to the product team via the feedback category: