It looks like federation from Hexbear to discuss.tchncs.de works, but not the other way around. For example, on db0 we can see a user reply to a Hexbear comment, but it doesn’t show up when viewed from Hexbear. Maybe this is an intentional side effect of how (de?)federation works, but this post seems to suggest we intend to be federated, we appear in their linked instances, and not in their blocked instances, while our linked instances shows them, but allowed does not (it has discuss.techncs.de though, which appears to no longer exist?)
Anyways, it seems like the relationship shouldn’t be so one-sided. Either neither direction should work, or both should, but maybe there’s just something I don’t understand here.
E: also adding a screenshot of my comment to the post, because while I assume y’all can see it, I don’t really fully understand what happens with posts/comments in this comm:

