Macbook battery not charging. Help please!!!!!

I have a Macbook Air M1 that is less than a week old. I noticed that when I put it in the charger, there is a mark of a socket on the battery and it says the battery is not charging. After a few seconds it changes to a lightning and charger sign. Sometimes when I connect with the iPhone 20 watt charger it is a straight charger, but if I disconnect and connect again after a second it says no charging again and after a few seconds charging. In the charger that comes with the MacBook, this also happens on the first connection. It is important to note that when it is a charger it is a good and fast charger up to 100%. What is the problem with the computer? Because this is a new computer that I received under warranty after the previous one (same model) crashed. It didn't happen on the other computer. Thanks