Hi there! I'm trying to validate the PRO license for a new development (staging) website, and I keep getting an error:
Your code is valid but looks like it has already been used on another site. You can revoke and re-assign within your Themeco account.
Now this is ridiculous because I've explicitly revoked the license from an old devsite and set it to this staging url. I even tried assigning it a license for a production site with the staging URL, still no joy. I never have this issue with my own servers, but this one is hosted with SiteGround.
I solved my issue after examining various other issues that occurred, and generalized the original post for anyone searching for a similar issue.
It seems that SiteGround's staging system works with Apache redirects, and forces the original (production) site's URL on WordPress even though the page is displayed at the right staging URL. As a result, the WordPress site URLs are all example.com rather than staging1.example.com, which is also what X/PRO's validation system reports to the validation service.
To solve this problem, simple force the correct URL in wp-config.php by adding these two lines below the WP_DEBUG settings:
Before redeploying to production, go back and return the URLs to the production URL. If you fail to set the URL back before deploying, it will break the URLs on the production site. (See Troubleshooting - Builder Preview Warnings)
Additional reading regarding SiteGround staging issues (and workarounds):