After installing Plesk Obsidian the following error is shown in UI:
PLESK_ERROR: Unable to configure the web server: Execution failed. Template_Exception: mkdir: cannot create directory '/etc/nginx/plesk.conf.d': No such file or directory mktemp: failed to create file via template '/etc/nginx/plesk.conf.d/server.conf.XXXXXX'
nginxwas installed before Plesk, most likely from nginx.org.
Plesk fails to generate configuration files if nginx was installed before Plesk.
This has been reported as bug ID PPPM-11215 which will be fixed in future updates.
Connect to the server via SSH.
Reinstall Plesk nginx package:
# dpkg --force-confmiss -i /var/cache/apt/archives/sw-nginx*
Disable/enable Nginx to rebuild configuration files:
# plesk sbin nginxmng -d
# plesk sbin nginxmng -e