Hi @user000
Thank you for posting your inquiry on the Auth0 Community!
I am sorry about the late reply to your post.
Unfortunately, as mentioned in this community post by one of my colleagues, the New Universal Login does not support the use of iFrames at this time. This community post addresses a possible solution if you are using NextJS for your application.
You can also view our knowledge article regarding iFrame login for a possible solution to the issue that you are facing.
You can upvote existing feedback posts such as Allowing Apps to be used in iFrames or New Universal Login Support for iFrames or even create a new one suitable to your use case.
If you have any other questions, feel free to leave a reply or create a new post if necessary.
Kind Regards,
Nik