I resolved this by moving phone to my ubuntu 18 laptop. i had to add the USB device per this page: https://android.stackexchange.com/questions/144966/how-do-i-get-my-device-detected-by-adb-on-linux
Started ubtouch and it's now installing.
It does a similar thing on my meizu Pro 5 although the emails are displayed and can be read after around 45 to 50 seconds has passed
@isolated-thinker probably no one replied to your question because nobody knows the answer 🙂
The only thing I can tell you is that there are a lot of issues with bluetooth in UT, as you can see in "The" Bluetooth Thread.