The sub-domains that you can secure with one Wildcard SSL Certificate have to be either 1st level sub-domains (e.g.: *.example.com) or 2nd level sub-domains (*.mob.example.com). You cannot secure 1st and 2nd level sub-domains with one regular Wildcard SSL Certificate.
If you want to secure 1st level sub-domains and 2nd level sub-domains, you have to get a Multi-Domain Wildcard SSL Certificate, or 2 separate Wildcard SSL Certificates.
For example, a regular Wildcard SSL Certificate allows you to secure:
- One main domain name (example.com) and all its 1st level sub-domains (*.example.com):
- Or, one sub-domain (mob.example.com) and all 2nd level sub-domains (*.mob.example.com):
In order to secure one domain and all its sub-domains as shown in the first example, you have to include *.example.com as a common name (domain name) when creating a CSR (Certificate Signing Request). If you want to secure 2nd level sub-domains, then you have to enter *.mob.example.com as a common name (domain name) when creating a CSR (Certificate Signing Request).