The report execution has expired or cannot be found. (rsExecutionNotFound)

Ccparkhill , v-yulgu-msft :

Another bit of info to add to this regarding the specified error, with a client-side fix.  At this point, I am using Microsoft Power BI Report Server Version 15.0.1107.166 with SQL Server 2019 Enterprise.

I have been using the URL adjustments for several years now with success, but suddenly got the nasty session expired error again and none of the recommended solutions worked, including URL tweaks.  These days I am using Google Chrome as the primary browser.  In this particular case, I have a paginated report running in an iframe on a web page that I have been working on intensively for the last 24 hours.  So after exhausting all the other troubleshooting options, I hit F12 (Dev Tools) and started looking for sessions/cookies.

The session which is expiring is stored as a cookie on the client PC (assuming UseSessionCookies is True, but even when I set that to False it didn't fix the issue 😞 ).  I found the misbehaving session cookie in Dev Tools under the Application menu item.  Then on the left side bar, under Storage > Cookies, the report server base URL was listed.  I clicked that and the session ID reported in the error appears as the Value of one of the cookies in the list.

I deleted the offending cookie, refreshed the screen containing the iframe, and there was the report!