Shark Robotic Vacuum Cleaner with Self-Empty Base

This Shark IQ robot vacuum includes an XL self-empty base. It's equipped with a self-cleaning brushroll. The system dimensions are approximately 48cm x 30cm x 38cm (19" x 12" x 15"). The base seems to be working well but the vacuum doesn't seem to charge properly. When charging it just shows a red battery light but won't move off the base. Selling as is for the base and the vacuum.