We have purched 2 times your theme, and as i can read on the instructions i can use these 2 licence keys for 4 domains.
I have already activated 3 times your codes, but i cannot activate it on the 4th domain.
As we can see, your purchase code is already activated. If you want to activate it again, you need to remove all the activations in your account first. You can do this on this page https://xtemos.com/my-account/
After this, you will be able to activate the theme with your purchase code without any issues. Note that you can activate it twice: one on your development website and one on the production.