Recently (last month or so) our ArcGIS web maps have begun intermittently breaking due to some layers returning the error: “Unable to establish a secure connection to the layer.” This occurs with layers from our ArcGIS server as well as public layers from ArcGIS Online. It seems to be caused by the browser redirecting from HTTP to HTTPS when accessing anything at Arcgis.com or its subdomains. In Chrome, you can temporarily fix this by deleting arcgis.com from HSTS, as described here: https://goo.gl/1AtLhl. I say temporarily because it seems to break again after some period of time, until you go and delete it again. Clearly this isn’t something we want our users to have to do to work around the problem. Any ideas how we can fix this?
Note: The setting for “Allow access to the organization through HTTPS only” in ArcGIS Online is turned off for our organization.