If you use WP Staging Pro with its license key activated on the production site and you try to activate the license key another time on another website or the staging site, you’ll get an error message like the one below:
You see this message because you’ve already activated the license key in one site, and your current WP Staging plan does not support more activated WordPress sites at the same time. For instance, the license key can only be activated on one website if you’ve purchased a single site license.
Let me explain why this might not be an issue:
If you get this message on the staging site, you can simply ignore it. You do not need to activate the license key on the staging site since all the push and cloning operations are done from the live site.
Just make sure to activate the WP Staging license on the live site and update the WP Staging Pro plugin on that site only.
If you already activated the license key on another (staging) site, deactivate it there and then activate it on the live website again. That’s all.