Hello Everyone,
I had a similar issue after installing SNAP 7.0 (downloaded on 2019/Nov/19) using the above procedure described by KenanV.
The messages when starting snap in the terminal was:
"Gtk-Message: 13:17:49.557:Failed to load module “canberra-gtk-module”
But after installing the module with:
sudo apt install libcanberra-gtk-module libcanberra-gtk3-module
And starting snap again, it all worked fine.
I use Ubuntu 18.04.2. (Linux 5.0.0-32-generic with x86_64 GNU/Linux OS)