DIAGNOSIS Physical proximity doesn't guarantee a good signal. The issue is likely interference from other electronics or signal reflection/cancellation.
FIX Move both nodes. Place them at least 3-5 feet apart (too close can be bad) and elevate them—on a shelf, not the floor. Ensure they're not right next to a microwave, baby monitor, large metal object, or dense brick/concrete wall.
IF THAT DIDN'T WORK The problem might be your main gateway's internet connection itself. Run a connectivity test on the gateway eero in the app. If that's poor, the satellites will inherit the problem. Focus on fixing the gateway's connection to your modem first.
HEADS UP "Poor connection" can also be triggered during a temporary ISP outage or modem reboot. Check if your main eero has a solid white light before troubleshooting the satellites.