Diagnosing whether a site is redirecting to HTTPS automatically.
We will be using the cURL utility to diagnose this issue. Please note that the utility is included in both Mac and Windows and you can access it by simply opening a command line interface.
To check this on a domain, go to a command line and type:
curl -I sitename
A correct result will look like this:
While an incorrect one will look like below:
200 is the OK response while 301 is the redirect response
Note: If a site has a Coming soon page, it should be returning a 503 status code to indicate the site should not be reindexed at that time. Google knows that when this status code is returned, it is to check the page again later on.
You can view more info about that here.