I have a few IPFire installations which are in use for a few years now. So the OpenVPN Certs were outdated. Despite deleting the x509 configuration and recreating the certificates, the message: "The host certificate is not RFC3280 compliant" remains. A closer look shows me that the ovpn.cnf are still outdated although my IPFire ist updated to Core 153 6553889 -rw-r--r-- 1 nobody nobody 2.5K Jun 14 2016 /var/ipfire/ovpn/openssl/ovpn.cnf After I changed the file to this one everything works for me now. https://git.ipfire.org/?p=ipfire-2.x.git;a=blob_plain;f=config/ovpn/openssl/ovpn.cnf;hb=refs/heads/core123
*** This bug has been marked as a duplicate of bug 13634 ***