Being that its saying its a 301 redirect, my understanding is you can't ssl login content via a 301 securely, as you're changing the POST / GET URL from the secure login form itself for password field.
This normally happens when you have multiple pages to login, where its redirecting to the original path required to confirm with the DB.
Upgrade the software and template with any patches.
I don't personally touch free forum software for many reasons, one is they're the most insecure, updates are spotty at best, and they stop running well as they grow due to lack of server software support.
Haven't touched Apache and any other web servers well over 10 years...
I stopped using Apache long ago. Too bloated. I've used NGINX for probably the last 6 years now. Won't go back. When my last forum got to about 300k posts, it was expensive and difficult to optimise on Apache, compared to NGINX. My main one is about 1.7million on NGINX, extremely fast page loading.
Much cheaper to run NGINX servers with forums on them than Apache. A fraction of the cost actually.
in Trips Old and Planning!