Macbook Pro M3 and Dual External Displays using Thunderbolt Dock

If you have the base M3 MacBook Pro, that supports two external displays only with the laptop closed. That means you need an external keyboard and mouse/trackpad, and you need to be on AC power.

The order also matters, you can't just connect the Mac to the dock since, you must connect one, close the lid, then connect the other. Apple's instructions are:

1. Connect the first display. This will be the primary display, supporting up to 6K resolution at 60Hz (or 4K at 144Hz).
2. Close the laptop lid.
3. Connect the second display. This will be the secondary display, supporting up to 5K resolution at 60Hz (or 4K at 100Hz).

If you have an M3 Pro or M3 Max chip, those support two displays with the lid open and don't need special consideration for connecting them, so if that's the case for you the issue may be the dock. What dock are you using? Note that many docks for Windows use MST protocols to drive multiple displays, and Macs don't support that.

If your MBP has a M3 Pro or M3 Max chip, it should support using two external displays without closing the lid.

The plain M3 chip appears to have a limit of two displays, total … like the plain M1 and M2 chips before it. All of the Mac notebooks that use plain M1 and M2 chips have a limit of one external display, period. Notebooks based on the plain M3 chip can pull the trick of redirecting the display output normally used for the built-in screen to a second, “lid closed” display.

Could you post the specific model number of the Anker dock - or a link to it’s description on the Anker site?

Anker makes several Thunderbolt docks, and it might help to know which one we are talking about.