macbook air not charging

I have a macbook air from late 2018 and it wont stay on with out the charger being plugged into it. But the light on the charger stays red and never green. if its not plugged into charger it goes into sleep mode or off. I purchased a new charger cord and the same thing is happening. I ran all updates needed and I also reset the SMC. Not sure what else to do at this point. Otherwise it works fine.