@Kate-overcast 

First, I will assume that you are referring to embedding a website into a Miro board.

"But the site is not whitelisted." - Are you receiving some sort of error or a prompt about a "whitelist"?

"The site is displayed square" - The perhaps you need to specify your desired embed.ifeame code dimensions.

If I am correctly understading your written description of the problem, not all websites will display like they are "inside the Miro board". You will need to click the embedded site at which point it will open in smaller window. 

It would be really helpful for us all if you were to write out exactly what steps you are taking - even better, include screenshots.

In the meantime, here are a few informational resources for your review:

- Embedding Media to Boards Help Center article

- another post on this forum about embedding websites into Miro boards