Hello,
You should be able to do so now. Every new member must make five posts that are manually approved by a moderator before they appear on the open forum. You hadn't hit that threshold but were posting in five year old swap threads where the posters hadn't been on in a while, which has been a bit of a flag for scammers in the past. So those posts were not approved. Now that you have made the threshold, you should be able to post private messages, and can contact those members directly to see if they are still looking.
ATB
Chris