When sending a URL to another person, the valid SharePoint URL throws two different errors on first then second page load. For example: https://oursites/communities/SP/Lists/ListOfUsers/AllItems.aspx
The first is:
Server Error in '/' Application. The resource cannot be found. Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.
The second is:
Sorry, something went wrong An unexpected error has occurred. Technical Details Troubleshoot issues with Microsoft SharePoint Foundation. Correlation ID: 00000000-0000-0000-0000-000000000000
The user opening the URL has appropriate access to view the content. The URL is correct. The web application, site collection, and list view all work for everyone else. The user can load the site from the base URL. The list loads when opening from Site Contents.