Many iPhone users after upgrading to latest iOS 11.3 releases by Apple are facing issue while browsing the website that can’t use any web browser to login from safari browser as it give the error “the browser application cache is unavailable at this time. please ensure the application cache is not disabled and you are not using this application in a private browsing session.”
The iPhone X/8/7+/6s and other model users are getting this error on a website, even related to sites which requires login (like company websites) and after this the error “browser application cache is unavailable at this time…” appears. Even when tried with other browser like safari, chrome, firefox the website still does not open. This is surely related to iOS 11.3 update as other android devices, and pc devices connect without issue to the websites. Even when tries with earlier vesion of iOS, the site opens up normally.
The issue is really annoying and problematic as on ios devices all browsers do not work safari, chrome, edge and firefox all get the same errors related to cache unavailable.
Fix 1: Use different browsers
There are many apps/browsers available on Appstore that you can use to open up the website eg, "browser & file manager” dolphin browser , opera mini browser, puffin browser that we have had success to open up the website. Lots of them are available to use as free while some comes with with minimal fee after a trial period. Try the free version of these app first and check your intended websites open or not.
Fix 2: Revert back to older version of iOS
Make sure you have a current back up and you can consider reverting back to older iOS version where the sites open up normally, until Apple comes up with permanent fix you always have option to revert back to older version.