My Garmin Fenix 5S (sw 25.0) stops charging at 36%

My Garmin Fenix 5S (sw 25.0) is not charging any more, it stops at 36% at then gets really hot.

used the clock for a run today as well, back home set it to charge again, but again it stops to charge at 36%…

What might be causing this? This started to happen some days ago.

Kind regards Christian