Can't sign commit with yubikey, GPG missing something

I don't know much about how yubikeys work, but I'm trying to sign a commit with one of them and I don't even know how to debug the problem. I got:

gpg --list-keys/home/lz/.gnupg/pubring.kbx---------------------------pub   ed25519 2018-11-30 [SC]      123456...ABCDEFuid           [ unknown] proton@srp.modulussub   cv25519 2018-11-30 [E]

and

git commit -m "hdle" -S error: gpg failed to sign the datafatal: failed to write commit object

and

gpg --status-fd=2 -bsau 'MyName <myname@protonmail.com>'gpg: skipped "MyName <myname@protonmail.com>": No secret key[GNUPG:] INV_SGNR 9 MyName <myname@protonmail.com>[GNUPG:] FAILURE sign 17gpg: signing failed: No secret key

PS: SSH login works with yubikey

UPDATE:

echo "test" | gpg --clearsigngpg: no default secret key: No secret keygpg: [stdin]: clear-sign failed: No secret key