After updating to newest fabric API blocks don't drop (I tried mining copper). As I have the same problem with blocks from at least two other mods (Epicurean and Extra Pieces), I thought I give the info to the coders.

What Cotton Resources version are you using?

cotton-resources-1.1.2+1.14.1-SNAPSHOT

and

fabric-api-0.3.0-pre+build.166

I try to have the newest version.

Ah, it looks like I need to make a new CurseForge update soon. The most recent version on our Maven is 1.1.4+1.14.1, which should fix the cascading failure issue we've been having. If that doesn't work, I'll take a deeper look; it might also have something to do with Epicurean's issues.

You're missing cotton main.

So, with 1.1.4 there was no difference, with 1.1.5 I got this crash: https://pastebin.pl/view/86b7dd05 (for reference, I deleted any mod except fabric api, 167 and cotton resources). I also checked for the newest fabric.

Looks like this was a missing cotton library, but feel free to submit a new issue if something more comes up.