I want to create a subdomain website in Plesk Obsidian, The issue was how to assign the SSL Certificate of the main domain.
I try to reinstall the ssl certificate of the main domain but it did not work, it keep showing that the component which is the subdomain is not secured and an info message saying that the SSL Certificate for the subdomain should be resolved automatically.
The main domain has wildcard domain security level config.
By default Plesk is not responsible for assigning the ssl certificate automatically for the subdomain, so you should configure that by yourself.
First, you need to create the subdomain using the Add subdomain button, once the subdomain is created you should reissue the SSL/TLS Certificate of the main domain make sure it set to
Secure the wildcard domain (including www and webmail), After that, on the side panel click application & domains then click on the subdomain application, open the tab Hosting & DNS, then click hosting, on SSL/TLS support section on the dropdown, you should see the generate ssl certificate for your subdomain, click & save.