diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 480398d10..4eedb99bb 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -95,6 +95,8 @@ Once you have completed the above steps, you are ready to build and run Monkeyty
 1. Run `npm install` in the project root directory to install dependencies.
 1. Run `npm run start:dev` (`npm run start:dev:nodb` if you skipped the mongo section) to start a local dev server on [port 5000](http://localhost:5000). It will watch for changes and rebuild when you edit files in `src/` or `public/` directories. Note that rebuilding doesn't happen instantaneously so be patient for changes to appear. Use <kbd>Ctrl+C</kbd> to kill it.
 
+**Mac Users:** If you get 403 Forbidden errors while trying to access the local server, go into System Preferences > Sharing and disable AirPlay Receiver - it also runs on port 5000 and takes priority, causing 403 errors.
+
 ## Standards and Guidelines
 
 Code style is enforced by [Prettier](https://prettier.io/docs/en/install.html), which automatically runs every time you make a commit(`git commit`) (if you've followed the above instructions properly).