Thank you for your post.
The WebViewer is not a browser. Information is sent to the OS Web API (Safari for Mac, Internet Explorer for Windows), and the page is processed and then displayed in the WebViewer. Since the Web API cannot display a sub-window on top of a web page (like the login page on top of the reminders page at https://www.icloud.com/#reminders, the default error from that web page is displayed.
Instead, you may want to have a button that executes "Open URL' with that web page, as it will then launch your default browser (possibly Safari on Mac) to display the full information from the browser.
Let me know if you need additional clarification.
I tried this (open in URL) in FileMaker Go 15, but I still get the "this application does not support your version of browser". I do have the option of "Open in Safari", but I'm trying to streamline the user interaction. Any suggestions would be welcome.
On my iPad Air running FileMaker Go 15.0.3 under iOS 10.2.1, I also get the "Failed to open "https://www.icloud.com/#reminders" message when I execute Open URL, but on subsequent attempts, it does work. If I close the file, reopen the file, and tap the Open URL button again, it works. However, if I exit the FileMaker Go app, relaunch FileMaker Go and open the file, I get the "Failed to open..." message again only the first attempt.
Can you confirm? If not, what iOS device are you using, and what version of iOS?
I wasn’t actually trying to access reminders. I read further and realized that the website I was trying to access was password protected, so I think that is the issue.