I’ve tried many times importing the theme: Deco, but it’s kept failing to setup and show the following information:
{ AJAX import error. Try to disable all external plugins and run the import again. If it doesn’t help, contact our support center for further assistance.}
However, I did remove and disable unnecessary plugins, still fail to import the theme.
While importing the dummy content your server throws an internal error as shown on the screenshot https://gyazo.com/c9f04bb5a740aca674c5a635039d4ea1
We checked PHP error logs but they are either empty or not enabled on your server. In any case, you need to contact your hosting provider and ask them to check the issue from their side.