Connect with .ovpn file fails (import from Windows installation)

[Alrik]

Hello OVPN-users,

I'm new to OpenVPN. I'm using the OpenVPN Windows client (on a Windows 10 PC), which works fine. Now I wanted to import my the configuration file (*.ovpn) from my Windows-installation to my OpenVPN app running on my Android 8 smartphone.

Thus, I copied the ovpn-file from my PC to my smartphone. When trying to import it, I get the following error:

"Failed to import profile - Selected file has incorrect profile configuration[inline], [inline]"

How do I have to change my Windows .ovpn (with integrated CA-certificate, as it seems) to get it working in my Android app? The configuration files in Linux and Windows seem to be identical.

What are the necessary changes for Android?

Thanks for any help!
Alrik

PS: Sorry if this question has already been answered in another post. I did my best, but did not find any helpful posts by using the search function.

[Alrik]

Correction: My smartphone is running on Android 9 (Pie).