dashboard logging out alone

Hi, lehcimoliveira ;

If the user broswer cookies for the PowerBI Sign in expired then you will give the login.  After the report is embedded in your web portal, or if a user opens the URL directly, the user is authenticated before they can access to the report. Below, the user has not signed-in to Power BI in the browser session. When they press Sign-In, a new browser window or tab may need to open, so ensure you check for pop-up blockers if you do not get prompted to sign-in. The user needs to sign-in each time they open a new browser window. After they’ve signed in once other reports will load automatically.

You can go for PowerBI embedded solution like App owns data/ User Owns Data for avioding login 

Or you can use publish to web and it will not ask for authentication to the report.

Best Regards,
Community Support Team _ Yalan Wu
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