you have an interesting configuration ( https://check-your-website.server-daten.de/?q=sustainableleads.com ):
There are 4 ip addresses:
All have the same content. But you have only redirects non-www -> www:
So you have 8 https connections, but all use two certificates:
expires in 80 days sustainableleads.com - 1 entry
expires in 80 days www.sustainableleads.com - 1 entry
and all https connections are secure.
So there is no wrong certificate, no insecure connection found. But if you don’t have a redirect, then http + www isn’t redirected -> this is unsecure.
So add redirects in the correct order:
- First redirect http + non-www -> https + non-www and http + www -> https + www.
- Then select one preferred version and redirect from your not-preferred version to your preferred version.
PS: You have small mixed content warnings.
This is inconsistent, if you use https, you don’t want a http as canonical. But browsers doesn’t show this as mixed content (they should, but this is another story).