iPhone 11 stops charging after a few seconds

When I plug in the lightening connector, the phone recognises it and displays the charging symbol to the right of the battery level indicator at the top right of the screen

after a few seconds, the charging lightning symbol moves inside the battery symbol, sometimes staying there for a minute or so, sometimes only for second and sometimes not appearing at all.

I have downloaded the latest IOS and tried a different charger and lead, but it still does the same thing.

I have also cleaned out the lightning connector at the bottom of the phone.