When I try to click Actions and press duplicate. I get "No internet connection". Doesn't work for test themes or when I try to duplicate the live theme.
Thank you very much for providing a screenshot of the error message you are seeing in your store admin. At this time I don't have any known issues that could be related to this. I would recommend doing some local troubleshooting and then if the issue is persisting please reach out to our live support so that we can escalate this to our technical team.
If the issue is still persisting after making those attempts please contact our live support to let them know. You can follow this link: Shopify Help Center - Contact Support, sign into your store account, search for your issue and use the contact support button at the bottom of the search results to see all our live support options.
Let them know what troubleshooting you have accomplished so far (screenshots of attempting it in a private window or or another device will assist our technical team) and they can escalate from there.