forums.wsusoffline.net

It seems like login/register/activation is not HTTPS? Why is that? If the login call is encrypted, I understand, but the login page should be HTTPS too (this whole forum should just be HTTPS). This wouldn't raise concerns.

Not the worst problem here. First step would be running a forum version that's actually up-to-date and supported. Unfortunately, the hosting provider seems to offer a quite outdated PHP version.

HTTPS would be the second step.