Thunderbolt ports only work on the right side not on the left any-longer when connecting LG Monitor

Burgerb wrote:

The Thunderbolt ports on the right side of my 13'MBP work when connecting to my LG Monitor, the ports on the left stopped working ... why? (I'm baffled :-) )

For context: The ports on the left worked just a few days ago. I took my MBP to work and connected the MBP via Display cable to another monitor. When I brought the MBP home the left ports stopped working. Meaning: I connect the Thunderbolt port from the monitor to the Left Thunderbolt port on my MBP and the display stays blank. But when connecting to the ports on the right side, the monitor comes up and everything works. (See video) 

System Info:

MacBook Pro (13-inch, 2020, Four Thunderbolt 3 ports)

Monitor: LG UltraFine Display

macOS: 12.3.1

Memory: 16GB

Graphics: Intel Iris Plus Graphics 1536

Any advice would be amazing.

Did you try rebooting?

The current stable release of Monterey including bug fixes, is macOS 12.4— I would start here...

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

On your Intel Mac you can —

Try resetting the SMC How to reset the SMC of your Mac - Apple Support

Try resetting NVRAM/PRAM Reset NVRAM or PRAM on your Mac - Apple Support

(get at least two-three rounds of the chimes when holding the NRAM Reset)

if no insight or resolve—Use Apple Diagnostics to test your Mac

Use Apple Diagnostics to test your Mac - Apple Support

Burgerb wrote:

Thanks. A reboot was enough to fix the issue!

Good computing Burgerb !