If you have a user experiencing a blank screen or gateway time-out error after an upgrade, ask the user to:
Click Ctrl + F5 when they are in the browser window. This will force the browser to retrieve the webpage from the server instead of loading it from the cache.
Clear their cache (browsing data) from their browser settings so that any previous sessions of ESs are not loaded. The steps to clear the cache will differ depending on the browser you are using. You will need to refer to the browser's help options for more information.
Open the browser as an incognito or private window (e.g. for Microsoft Edge you would use CTRL+SHIFT+N after opening the tab). You will need to refer to the browser's help options for more information.
Should the issue persist raise a case online and reference this article so we can assist you further.