battery stopped charging, new batteries do not help

Laptop has been working with linux for years. Suddenly it stopped charging the battery. I have replaced the battery twice, and the charger. Original battery boots up, shows zero charge. Replacement batteries will not allow laptop to even boot. Remove the battery and it starts on the charger just fine. Hotswap the battery in, and it displays a battery icon without ANY charge level output. Amber light flashes on the outside battery indicator. Do not know what to try next.