apple usb c to HDMI adapter does not work but dell does

Hello Max Zorn,

To help determine a cause, we'll want to isolate things a bit more. You mentioned testing the adapter with a monitor and it working. To confirm, was that monitor connected to your MacBook Pro as well?

If the behavior occurs with multiple projectors or monitors you use with your MacBook Pro, updating the software can help us begin to isolate things a bit more. Check out Update macOS on Mac for those steps.

1. "From the Apple menu  in the corner of your screen, choose System Settings or System Preferences.
   1. If you chose System Settings, click General on the left side of the window. Then click Software Update on the right.
   2. If you chose System Preferences, click Software Update in the window.
2. Software Update then checks for new software. 
   1. If Software Update finds new software, click the button to install it. The button might be named Update Now, Upgrade Now, Install Now, or Restart Now, for example. You might then be asked to enter your administrator password.
   2. If Software Update says that your Mac is up to date, then no new software is currently available for your Mac model. Software Update shows only software that is compatible with your Mac."

We look forward to hearing the results.

Cheers!