The license key you have been provided has only one activation allowed per site.  If you activate this license on a site, it will only work on that domain.  If your license key doesn’t activate, the first step would be to verify your license information in your Account page.
To access your license information:
Click on the Account link in the Main Menu
Log in with your username and password
Click on Subscriptions in the Main Menu (under Account)
Under Your Account, click on View Licenses
Here you will find all the information regarding your license.  You can click on the key icon ()  to view your license to verify that it is correct.
To find out what domain your license is activated on, click on Manage Sites.  Here you will see which domain your license is activated on.
If this domain is not the domain you are currently using, you can click Deactivate Site which will decouple your license from this domain name.  You can now go back to your Solar Wizard plugin and activate the license again.
Should none of this work and you are still having problems, please contact our support here https://solarwizardplugin.com/#contact