The only thing in there that I found was wrong for my device is the location to put the new certificates. In the guide it says /tmp/openvpn, but I found that the correct location is /usr/openvpn (which makes sense, you don't expect /tmp to be a permanent location).

FAQ regarding OpenVPN Connect Android | OpenVPN certificate verification failed : x509 – certificate verification failed, e.g. crl, ca or signature check failed This is an error that tells you that the certificate could not be verified properly. This can occur for example if you are using an MD5 signed certificate. Setting up OpenVPN with Certificates - Cult of Tech.net May 02, 2016 Configuring OpenVPN Server using X.509 Certificates Dec 11, 2018

Connection Error X509 "Certificate Verification - OpenVPN

DeprecatedOptions – OpenVPN Community Jul 17, 2020

certificate - OpenVPN Access Server - Encounter the

When clicking the "More details", the reason states that "X509_V_ERR_CERT_HAS_EXPIRED: certificate has expired". But then I have the option to connect anyway. And I checked more for more info from the OpenVPN admin webpage, the Certificate "Validation Results" section displays: Web Certificate/Key validation results. OpenVPNクライアント(Windows,iOS共に)接続できない - Google … Apr 02, 2017