Hdmi output failed

I purchased from Amazon on Nov 15th the usb-c hub 10 in 1 model CB-C89 for my new MacAir M1. After a short while the hdmi was temperamental, but now it is not connecting at all to my monitor with “can’t find source” message on my monitor. the monitor and hdmi cable work as i tested with a dvd player. The hub’s usb and Ethernet connection still work fine. any ideas?