Embed Report to Sharepoint - iFrame + "sign in again"

[stalerik]

I have embed a Power BI report into a Sharepoint Online Modern Page using iFrame.  I am doing this because I want to take advantage of the URL flilters and custom height/width options that are not allowed with the basic "Embed to Sharepoint Online" web part option.  The report is shwon on the page correctly, but after awhile (1 hour?), the report goes to a "sign in again" mode in order to see the report.  How do I customize my report so the Sharepoint user (who is logged in and has a Power BI Pro account), doesn't have to repeatedly sign in separately to the Power BI service?  If the user is logged in to access the Sharepoint page, I'd like the credentials to automatically pass through to the content on the page -- like the Power BI iframe embed.  Thank you!!