Konqueror don't access FreeBSD forum's

With konqueror I cannot access at freebsd forum's and it display connection refused, while firefox access fine without problems.
Why? Ideas?
I'd like to set konqueror like default browser...
There is not enough information to help you. Do you have the same connection settings in both browsers, proxy etc?
Does konqueror open other sites? Have you tried Ctrl-R when it fails? It's happened to me on my workplace network, that www/firefox opens the Forums from second attempt.
I don't use/have konqueror, however I see no reason why it may not open forums.
Even text-based www/w3m and www/links browsers work fine here.
The only thing I can think of would perhaps be your encryption settings in the browser. Possibly try checking to see if TLS1, 1.1 and 1.2 are checked. SSL2 and 3 should not be checked since they are long defunct but some sites may still be serving at SSL3 level. I can't tell you where to look for those settings though since I haven't used konqueror in years.
I think I had this some time ago trying Konqueror. Iirc it had something to do with https and Konqueror just being too old and unmaintained. It's probably best to switch to a more recent browser.