why iphone 12 stop charging suddenly

you should be a bit more descriptive..

• won't charge at all?
• charges to 80% and then 'stops'?
• charging wireless or with a cable?

have you tried a different method of charging? (ie, wireless isn't working.. try a cable)

have you tried force restarting your iPhone? Instructions below

• Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then press and hold the Side button until you see the Apple logo.

then there is the article at the top of the page you can check out

If your iPhone or iPod touch won't charge - Apple Support