I also had such an issue with 22.7.4.Please check if the OpenVPN baemon is running; at my setup it crashed at startup!Removing the CRL from the OpenVPN config seems to fix the issue.
Fatal error: Uncaught Error: Call to undefined method phpseclib3\Crypt\EC\PrivateKey::withPadding() in /usr/local/etc/inc/certs.inc:666 Stack trace: #0 /usr/local/etc/inc /plugins.inc.d/openvpn.inc(834): crl_update(Array) #1 /usr/local/etc/inc/plugins.inc.d/openvpn.inc(1115): openvpn_reconfigure('server', Array) #2 /usr/local/www/vpn_openvpn_server.php(450): openvpn_configure_single('1') #3 {main} thrown in /usr/local/etc/inc/certs.inc on line 666
opnsense-patch 67e4a1d