Medion battery is not recognized?

My laptop is a Medion Akoya E6411 with Windows 10. The problem started with the error message "Mains, not charged". If I remove the charging cable, it crashes immediately, but also with cable more often. Another error message that appears more often is: "No battery was found." I have already uninstalled and reinstalled the drivers. Also to remove and reinsert the battery did not help. In addition, from time to time the light in the lower left flashes red.

mean the left lamp.

Probably. Defective battery?

That could be, but I would like to know more about it before ordering a new one.

Only a technician can tell you more about customer service.