If you see the "Please enter a valid key" message after you have tried to activate the extension, it is most likely caused by the fact that your actual base URL in Magento® admin panel is not equal to the website URL for which the extension license was purchased. You may have specified your license URL as www.domain.com while your actual URL is www.domain.com/smth or domain.com:80, or you are still in the process of development and are using the URL of your staging site.
REMEMBER! The website URL in your license must exactly match the Base URL of your Magento®. If the website URL in your license is, for example, abc.com and the Base URL of your Magento® is abc.com/shop, then the activation key will not work.
The screenshot below shows the website URL to which your license key is assigned. You can find it in your GoMage account at the Downloadable Options section:
The second screenshot shows the base URL of your Magento® site which you can find in your admin panel at System -> Configuration -> General -> Web -> Unsecure >> Base URL field:
In case your base URL in Magento® admin panel is different from the license URL in your GoMage account, and that base URL is going to be used permanently, you need to contact our Technical Support Team and ask your license URL to be updated. You may contact our Support Team at https://www.gomage.com/contacts/
Note that you cannot use your production key to activate the extension on a developer or staging website. You cannot use your developer website URL as your license URL when you purchase the extension. In order to activate the extension on a developer or staging site, you must request a free developer key from our Technical Support Team.