"Domain ... is not allowed" error. What does it means and what to do?
This error appears when the website domain you use the extension on is not in the list of allowed websites domains for this license. It is usually happens when you purchase the Personal License, which allows you to use the extension on a single website, but you are using the extension on several websites.
When you purchase Extended License, you can use the extension on several websites. And you still have the ability to limit the websites that are allowed to use the extension on.
You can manage the list of the websites that are allowed to use the extension on in your account. If you purchased a Personal License, then a single website domain can be set to limit the extension usage. So if you want to use the extension on several websites, you need to purchase a Personal License for every website or consider to purchase an Extended License. The detailed information about licenses can be found here: https://allforjoomla.com/licenses-compare
If you have several domains that are pointing to a single website (aliases, a domain per website language, etc...) please submit a request in the help section indicating the License Key and a list of those domains.
If you purchased an Extended License, you can manage the list of website domains that are allowed to use the extension on in your account by settings each website domain per line in the field of allowed websites.