This issue usually occurs when the website hosting the Power BI report does not have a valid SSL certificate, causing the browser to consider the page as untrusted. To resolve the issue, you need to obtain a valid SSL certificate for the website and properly configure it to encrypt the communication between the website and the user's browser. You can get an SSL certificate from various certificate authorities, and you can also obtain a free certificate from services such as Let's Encrypt. Once you have the certificate, you will need to follow the instructions provided by your certificate authority to install and configure it on your website's server. After the SSL certificate is installed, you should be able to embed the Power BI report in your website using an iframe without any issues related to the website being untrusted.
