Error on Embed Appsheet

[Jewel]

I am trying to embed my Appsheet on my Website, following this recommendation.

(also adding “< /iframe>” after the html)

On the website, after choosing my useremail, I get:

If I click on “Next” I see:

I really don’t know what else to do… Any help please…??
Note: It is not deployed yet, but theoretically if I use my useremail I should see it, right?
Thanks!!