I got the same problem. My S9 got wet, then I rechearged normally and it worked. The day after I got the known message and I couldn’t rechearge the phone. I used a hairdryer and it didn’t work. I thought maybe the phone got some soap on the pins so I put it in water and moved it so soap was gone. Then I dried it and it didn’t work. Then I powered it off, put it in charge and then repowered it on and the message was gone.