When connecting via terminal and you get this error:

Note: Cannot ioctl TUNSETIFF tun: Operation not permitted (errno=1)

And in logs:

Options error: --key fails with '/home/user/pathto/VPN/some.key': No such file or directory (errno=2)

set an absolute path to the openvpn crt, ca and key files.

ERROR: could not read Auth username/password/ok/string from management interface

Gnome network manager wasn't setting the proper Cipher in VPN conn>Identity>Advanced…>Security. It was set as “Default”. Change it to exact cipher shown in “data-ciphers” line in openvpn config file itself.

• Ubuntu 24.04
• Gnome Network Manager ver. 1.46.0