Problem how to configure http and https the right way

Hello,
my problem is that I have a wpsite running under http. But when i get a redirect the refrerr is a http and the domain is showing a https as incoming url( just use this domain for redirecting traffic). I only want to have the http and not https, what should I do to get this working correctly? I try the things assumed in the other threats, but still not working like I need...