Are you able to DCC send a file to someone? Not being able to DCC chat generally means you also cannot DCC send - which means it's a good idea to check out the
Can't DCC Send sticky thread and follow the advice given there.
To reiterate the general guide in that thread, if you have a firewall or router, then you need to forward ports in them and then set the same port range in
ALT+O >
Connect >
Options >
[Advanced...]. Make sure you try to DCC chat 2+ people to make sure it's not the receiver having issues (which is unlikely but possible).
Regards,
