To start with make sure you are using the charger and cable that came with your system.
The USB-C cable Apple supplied is designed for power unlike most other USB-C cables which are designed to be for data. The wire gage within the cable is thicker for the power feed needed for your system unlike the data cable which is using the thinner wires for data and low current device support.
You’ll need to work through a process here to isolate out what has failed. Often times the charger or the cable has failed or is the wrong part. Unlike older MacBook Pro’s there is no charging light so you just don’t know whats happening. I would recommend getting a USB-C power meter Satechi USB-C Power Meter Tester it will allow you to see whats happening.
You may want to visit an Apple Store to have them check your system. Hopefully you still have warranty coverage or have AppleCare+ extended coverage.