Anker Atom III Slim

I am not able to charge my mac 2016 (Usb C to magsafe 2) through, it used to charge fine not anymore (is it after Big Sur??) It starts charging initially and after minute or two stops charging. I have to reset the charger then to start the charging again, same thing, no other devices are connected. I have even tried to turn the mac off (shutdown) and charge, no success.
It was doing everything right till so long.

Did you try a different cable? A different outlet as well?

Ohh yes, everything.

That sounds like an overloading of the port, somehow your power draw went up, above what the charger can handle.

You have this ?

https://www.anker.com/products/variant/powerport-atom-iii-slim-four-ports/A2045111

That’s a 45W port

PIQ 3.0 (USB-C Port): 5V ⎓ 2.4A / 9V ⎓ 3A / 15V ⎓ 3A / 20V ⎓ 2.25A

So probably what has happened is your Mac has begun drawing more than 2.25A at 20V and so tripping the port shutdown.

Look for ways to lower the draw. One simple way is to begin with the laptop charged, and use the charger to simply keep the Mac charged so it never goes above 2.25A.