Returns an error when updating my Homebrew

Question

I'm trying to update my Homebrew using brew update but it returns the following error:

fatal: 'origin' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
fatal: 'origin' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
Error: Fetching /usr/local/Homebrew/Library/Taps/jonj/homebrew-old-openssl failed!
fatal: 'origin/master' is not a commit and a branch 'master' cannot be created from it
fatal: invalid upstream 'origin/master'

Answer 1

Error: Fetching /usr/local/Homebrew/Library/Taps/jonj/homebrew-old-openssl failed!

When you brew tap <user>/<repo>, Homebrew will by default clone github.com/<user>/homebrew-<repo> into your Taps directory, see e.g. the docs, Is there a special meaning of the / (slash) in the name of the brew?　Or is it just a slash as a string?

In this case, at some point you did brew tap jonj/old-openssl, but that repo no longer exists publicly (currently a 404). To remove it, you can run brew untap jonj/old-openssl.