Diagnosis
The internal battery has likely failed or the USB-C charging port is damaged. An amber light with no charge acceptance points to a hardware fault.
How to Fix It
First, inspect the USB-C port in the speaker's silicone strap groove. Use a flashlight. Look for bent pins, lint, or corrosion. Clean it gently with a dry toothpick. Try a different USB-C cable and a different 5V/2A power adapter. Plug it into a wall outlet, not a computer.
If That Didn't Work
The lithium-ion battery is defective. It cannot hold a charge. This requires a battery replacement. Contact Bose support for service options. Do not attempt to open the sealed unit yourself.
Heads Up
Never use a fast-charging adapter rated above 5V/3A. This can damage the battery management system. The speaker only supports standard USB-C PD up to 15W.