[pgadmin-support] GUI App: "The application server could not be contacted."

Attempt to start pgadmin4 yelds message box with "The application server 
could not be contacted." error.

Is there any logs or something I can check?

Name        : pgadmin4-v1
Arch        : x86_64
Version     : 1.5
Release     : 2.f25
Repo        : @SystemFrom repo   : pgdg96

Linux 4.10.14-200.fc25.x86_64
Fedora release 25 (Twenty Five)