I have 3 ASP.Net Webforms sites using AAD B2C single sign-on, which is working perfectly fine an all browsers. However, I cannot get single logout to work in Edge or IE11, but logging out of each site individually works OK. When using the likes of Chrome or Firefox it works flawlessly - logout of one site, go to the others and, say, refresh or click a link and I'm then logged out.
The Logout URLs are all set correctly in B2C, otherwise it wouldn't work in any browser. What I have found is that when logging out from Edge and IE11, a request to each of the Logout URLs is never sent, so consequently the code I have on the logout pages to complete the logout and clear all sessions and cookies never fires. I've found nothing online to suggest why this could be happening. Can anyone help?