Iframe not working for cloud reports

Using Django Templates & Frontend
1

we have a dashboard portal, which is based on Django framework.
There are 2 types of PowerBI report in it, server based and cloud based.

When we click on server-based report, it opens in iframe.

When we open Cloud based report it is asking for sign in, and after clicking on sign a blank screen is popping up. basically Iframe is not working

2

Nobody will be able to help without more information.

We would need to see the relevant code - such as templates - to have a chance of diagnosing the issue.

Although at first reading it sounds more like an issue with PowerBI, which I know nothing about.