Zend certified PHP/Magento developer

Cannot find GPG Key

Please help me debug this set of terminal commands.

I have created a GPG key and added it to github, and am trying to sign my commits:

me@my-macbook myproject % gpg --list-secret-keys --keyid-format=long
[keyboxd]
---------
sec   rsa4096/CMC8D2G96B994245 2023-10-27 [SC] [expires: 2025-10-26]
      07A38FD8F66EBD7597K3ID51CMC8D2G96B994839
uid                 [ultimate] gpgunm <1234567+gituser@users.noreply.github.com>
ssb   rsa4096/078974E15960FC14 2023-10-27 [E] [expires: 2025-10-26]

me@my-macbook myproject % git config --global user.signingkey CMC8D2G96B994245
me@my-macbook myproject % git commit -m "Fix vulns"
error: Couldn't load public key CMC8D2G96B994245: No such file or directory?

fatal: failed to write commit object
me@my-macbook myproject %

As you can see, I’ve listed keys, and attempted to set my singing key, but when I commit git says it can’t load the public key because there is no such file or directory.