This was a problem for Pokémon Showdown recently. We use HTTPS for logins and some other things, which stopped working a few days ago for users using MitM antiviruses and Firefox.<p><a href="https:&#x2F;&#x2F;twitter.com&#x2F;TonyFlygon&#x2F;status&#x2F;684756701027954689" rel="nofollow">https:&#x2F;&#x2F;twitter.com&#x2F;TonyFlygon&#x2F;status&#x2F;684756701027954689</a><p>(Example user complaint.)<p>There&#x27;s no way to detect whether or not an HTTPS iframe has failed to load, so my workaround was to fall back to HTTP if the HTTPS iframe didn&#x27;t load within 2 seconds. We still switch the connection over to HTTPS if the iframe does eventually load.<p>I&#x27;m kind of confused by why so many users thought it was a Pokemon Showdown issue, specifically. Doesn&#x27;t Google default to HTTPS? PS shouldn&#x27;t be the most significant website they have trouble with.