One of my clients now doesn't want to use a SSL certificate. But the home page of their site has been indexed with HTTPS. I have already redirected HTTPS to HTTP but it shows a warning every time.
Is it possible to redirect without a warning?
If you don't have a valid SSL certificate, then it's not possible to redirect HTTPS to HTTP without a warning.
To properly issue the redirect, the site needs to have a valid SSL certificate. And if the site has a valid SSL certificate, then at that point it usually makes more sense to just serve the site over HTTPS.