Pgadmin 4 Not working in ubuntu 18.04

Question

I have installed postgres 10 and pgadmin4 in my Ubuntu 18.04 version. everything went fine. I cannot open the pgadmin gui. what might be the reason. it simply wont open. Does it require Qt? how do i check if I got Qt on my ubuntu? PS: (Also Teamviewer App is also not starting up). Looks like it uses PyQt for the GUI of the application.(atleast that what i heard) PgAdmin 3 is working fine. These are the steps I have done.

1. Create the file /etc/apt/sources.list.d/pgdg.list and add a line for the repository

   deb http://apt.postgresql.org/pub/repos/apt/ bionic-pgdg main
   

2. Import the repository signing key, and update the package lists

   wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
   sudo apt-get update
   

3. install posgtresql

   sudo apt-get install postgresql-10 
   

4. install pgadmin 4

   sudo apt-get install pgadmin4
   

EDIT: Launching from the command line, there is a first output:

`QApplication: invalid style override passed, ignoring it.`

then as @DennyMueller mentioned, a "Fatal Error" pop-up window saying:

`An error occurred initialising the tray icon`