brew update fails to download json

[superbonaci]

brew doctor output

$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  brew-pip
  exa

Warning: You have unlinked kegs in your Cellar.
Leaving kegs unlinked can lead to build-trouble and cause formulae that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
  python-certifi

Verification

• My "brew doctor output" above says Your system is ready to brew. and am still able to reproduce my issue.
• I ran brew update twice and am still able to reproduce my issue.
• This issue's title and/or description do not reference a single formula e.g. brew install wget. If they do, open an issue at https://github.com/Homebrew/homebrew-core/issues/new/choose instead.

brew config output

$ brew config
HOMEBREW_VERSION: 4.1.12
ORIGIN: https://github.com/Homebrew/brew
HEAD: aa2a77b1f1ac1539e69e186bad1d569100448987
Last commit: 8 days ago
Core tap JSON: 24 Sep 13:27 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: ["--no-quarantine"]
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 2.6.10 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: octa-core 64-bit arm_firestorm_icestorm
Clang: 15.0.0 build 1500
Git: 2.42.0 => /opt/homebrew/bin/git
Curl: 8.1.2 => /usr/bin/curl
macOS: 13.6-arm64
CLT: 15.0.0.0.1.1694021235
Xcode: N/A
Rosetta 2: false

What were you trying to do (and why)?

Try to update

$ brew update
Error: Failed to download https://formulae.brew.sh/api/cask_tap_migrations.jws.json!

[superbonaci]

Looks like has been fixed in server side.

[MikeMcQuaid]

This was a duplicate of a pinned issue. Please check for existing issues before opening new ones: #15998