Ubuntu can not find python3, which is intalled

I have Python installed on Ubuntu, as it appear when I execute on terminal:

$ python -V Python 3.7.3

But some issues which depend on Python 3 are not working, I just cant execute Skype, Synaptic…

When I try to re-install Skype it returns the following error:

$ sudo apt install ./skypeforlinux-64.deb … E: Package python3 needs to be reinstalled, it was not possible to find such file.

I would be grateful if someone could help me.