Currently due to technical limitations, a valid license key is needed for each domain and subdomain where Maps Marker Pro is installed.
If you are using subdomains just pointing to another part of your main site (e.g. for language choices like de.yourdomain.com), this does not count against your list of available licenses. In this case, please open a support ticket and we will add your subdomain to your list of valid license instances manually.
For a future release we plan to add wildcard support for license validation, so that every subdomain of your main domain automatically gets validated without counting against your list of valid license instances (*.yourdomain.com) – this will also include staging and development domains, which now also do not count against your list of valid license instances but which also have to be added manually by us.