Hello,
I am unable to register the wordpress theme I bought some years ago. I have two installations: one is on localhost running for development purposes in my LAN, the second is the live website.
The localhost installation cannot be registered no more.
Any help there?
Hi @R99-Photography and welcome!
Typically, registration of themes is intended for production sites. However, if you contact the author, they should be able to help get you sorted. https://help.market.envato.com/hc/en-us/articles/203039054-How-to-contact-an-author
Hope that helps! 
I don’t know how you work, but I develop and update my website offline (aka on my LAN), then I move on live website.
So I need to register the development OFFLINE version if I wanna use it.
Yes, that is a common and reputable development strategy. Not all themes require registration – but when they do, these registration systems are implemented by the author, not Envato.
And unfortunately they almost always fail to address development installations in these systems. In a worst case scenario, you can still update the theme manually.
If you’re saying that you wish to activate locally instead of on production, and are unable because of some error (e.g. license has already been activated), then yes, you can contact the author to clear that.
Thanks!
Roger, thank you sir.
I’ll proceed with a manual update at this point, because premium plugins with the theme (Uncode) could not be installed automatially by the the theme’s menu options.
Bye.