Nest Thermostat Battery Replacement Issue

Hey everyone, I recently had an issue with my Nest thermostat where it kept powering off due to a low battery. I followed some YouTube guides to replace the battery, and now I’m trying to recharge the unit using the USB port at the back of the display. However, I’m encountering a problem where the thermostat shows a message saying, ‘Please attach the display to its base.’ When I do this, nothing happens except for a faint green light. I’m not sure what I’m doing wrong here. Has anyone else experienced this? Any advice or tips would be greatly appreciated!