create a file called credentials.conf in your openvpn-aio-client folder, on the first line paste your vpn username, on the second line paste your password, save, try running the container again. I use PIA, in my openvpn-aio-client docker appdata folder I now have 4 files, ca.rsa.2048.crt, credentials.conf, crl.rsa.2048.pem, and openvpn.ovpn. I don't think the pem file is needed since I have the crt but it was part of the download so I left in.