Note: This article has the reference to the issue with the fix available:
"Updating the administrator’s default SSL/TLS certificate via CLI corrupted the web server configuration."
- Plesk Onyx 17.5.3 Update 21 05 September 2017 (Linux)
Updating the Plesk default certificate causes Apache misconfiguration because configuration files still contain information about outdated certificate files that no longer exist in
# apache2ctl -t AH00526: Syntax error on line 109 of /etc/apache2/plesk.conf.d/server.conf: SSLCertificateFile: file '/opt/psa/var/certificates/cert-QWssIy' does not exist or is empty Action '-t' failed.
This is an internal issue with ID # PPPM-6136 (Updating certificate file causes webserver crash), which is planned to be fixed in future product updates.
As a workaround, reconfigure Apache:
# /usr/local/psa/admin/bin/httpdmng --reconfigure-all