Trading card bots like Steamcardexcange?

Same set 1:1 at https://steamtradematcher.com/

If you're using ASF it has matchactively.
Else there's a good list of 1:1 trading bots: https://asf.justarchi.net/STM

Same set, use steamtradematcher. Different sets, steamcardexchange is the only one I know

Question about steamtradematcher:

I use it all of the time with friends. However, especially if I'm looking at a bot's inventory, when I click the "Offer a trade to <insert name here>" link, I end up on a new tab that errors out with a "Forbidden" error. Anyone else have this issue?

Beyond that link at the top, how do I initiate a trade with a bot? Like, if I'm looking at the inventory, why can't I just click on the card set I'd like to trade and have that come up in the Steam trading window?