Charging error symbols on Fairphone 5?

Yesterday I missed low battery and my Fairphone 5 shut down during use.

I meant to charge it over night with my usual charger+cable but today it is cold and black and would not switch on when pressing the button.

I connected another charger with another cable (a combination which worked before).

I get the Fairphone text on black background and then I get 2 different symbols:

  1. a battery with a red bar at the right (flat minus side) and a flashing plug inside the battery

  2. a battery with a red bar at the right (flat minus side) and a crossed out plug inside the battery

Can anyone help me with the meaning?

I know there is some sort of issue, but what exactly? Sorry that I can’t show pictures, but it is my only mobile.

PS: I found the second image here: New FP4 won't boot / charge after battery discharge