I have my SamsungS21 for less than 5 months and since the third month I have constantly the warning message of moisture detected in charging port! My phone has not been exposed to moisture and I have cleaned out the charging port and even the charger end. I've followed all the steps advised on the warning message and still had no luck! This message has appeared 4 times in the last two months and took minimum 4 days to dissapear, even doing all the procedures, cleaning, hair dryer, rice etc. Then during this time, I am using my wife's cellphone to charge mine wireless. I've never had any problems with my previouses galaxy, but after this I will think better after buying a new one. And I see also that this problem seems to be very common to other users.
@Members_AzMbeoY: Please can you try heading pressing the Volume Down and Power buttons together for around 10 seconds until your S21 restarts. Don't worry, this won't affect your personal data or settings. Now, head to Settings > Apps > Tap the 3 lines with the downward facing arrow, to the right of 'Your Apps' > Show System Apps > OK > Scroll down and select 'USBSettings' > Force Stop > Storage > Clear Cache > Clear Data. Let me know if this helps.
I've had the same problem with my S20 plus, I don't care what anyone says, it's a software issue if your phone has been kept dry!
The way to remove the constant warning & get it charging again is to plug it into a running laptop/pc & the warning will go & then you can plug it into your proper charger. Mine hasn't done it for a while until yesterday when I bought a USB c card reader with OTG built in & the moment I stuck it into the phone... Boom, moisture detected! So it's 100 % a software problem.