I own 3 HEXAs and use Android devices with the HEXA App for control.
I believe that you may have a Wi-Fi Connection issue. Go to tools on your phone and make sure that Wi-Fi is enabled and searches for your HEXA (while HEXA Powered ON). You cannot enable the HEXA App for controlling your HEXA unless a blue dot on the same line as the HEXA unit you have registered, appears on the first screen which has “HEXA” in bold at the top center of your screen and “Refresh” at the top right. Touch the “Refresh” when the Blue Dot appears and all will make sense. The connection does not happen quickly and your HEXA’s top LED must be Blinking Blue in order for the App to connect with your HEXA. This usually takes ~20 seconds.
A little patience is usually what is need.
If you have a newly purchased HEXA this should work. However, if it is a used HEXA (previously owned) you have to follow the Reset procedure in the manual. My first HEXA was previously owned and continuous failures to connect to the App drove me crazy until I found the Reset procedure (requires 6 Dupont Wires with Female ends).
Good Luck and let me know if you get it to work.