Hello all! I try to connect to an OpenVPN server that requires a username and password. I entered and saved, both, username and password, but when I go to "edit" the configuration file in NetworkManager (i use network-manager-openvpn-gnome). But I can see it saved in gnome-keyring. Using Lubuntu 16.04. Have tried reinstalling network-manager and network-manager-openvpn-gnome

You came very close to saying what problem you are having.

Hello. Welcome to this forum.

The forum is very helpful with linux distros.
This is because linux distros are enjoyed by people.
However, they are a very small group of people compared to Windows and macOS.

I'm afraid you will not find answers to successfully using OpenVPN on this site.
I speak from personal experience.

You guessed it, you need to go elsewhere.
It is possible to download tor and then use the tor browser to see if there are sites which help you to use OpenVPN.
I haven't tried this yet. But I have tor browser.

Alternatively, OpenVPN may be just a pile of bullshit.
In which case, just stick to tor.
It's not pretty, but it's anonymous.

I recommend you find a good wiki on line for OpenVPN. The Arch Linux site has a good one, you could learn a lot of general stuff there on OpenVPN and apply it to whatever distro you are using.

Saving the login credentials is often done with a "login.conf" (or similar) file provided by the service provider or company to which you are trying to connect.

I'll stop there - my VPN expertise is limited. Perhaps others will chime in.

Cheers !