Solved it on my own. You can add this to the troubleshooting tips. Try factory resetting the Deco's with FW 1.5.0 (yes, destroy and recreate the network) before reattempting the WebGUI. I was able to...

I am getting the same exact error. The provided Windows utility simply doesn't work. It rejects the login just like for the last poster. If it helps, I am using a Windows 10 64-bit OS, like most...

@Wobbo I am very confused. I found a different thread, where a 1.4 beta made a web GUI available. I even found that a non-standard port was listed. I upgraded all mine to the latest 1.5 as well....