I have the new A8+, now in Malaysia we are in the monsoon season. I have started to get this notifications. I was able to solve it some days ago by just keeping the phone a couple minutes in the sun, but now is constantly reaning!!! So, i will be without phone until the monsoon stops because i'm not able to charge my phone? Are you kidding me? This is the most stupid thing that i have seen in my life!
I know, for a fact, that this is not because phones or chargers are wet. I'm in Colorado- technical desert. Humidity 10%. (That's just backdrop because none of that matters. ) This has been done dozens of times with the same results- throughout the day, I charged my phone in my work truck, and received no errors, and I mean I'm charging it for hours, but 99% of the time, when I restart my phone, the moisture detected error will come up. So, before turning off, the phone is completely fine and charging. Turn it off and back on, immediate error message, so I unplug the cord. It will keep giving me the error message for roughly the next hour.
I am having this problem too, but like another reader, I cannot fit a Q-Tip in my charge port. Perhaps you folks have older phones with larger ports? Mine is a Galaxy 9+. Were you talking about a special brand of mini-Q-Tips?
These magnetic cables have fixrd my issues. They have a a connector that you leave in you the charing port of your phone and it seals that port. I have been using this for about a month with no issues. Befor that i was having issues almost everyday. Here is a link to where i bought them form www.bricksomeactual.com
I also have the same problem for a month. After one sofware update it the phone charged a couple of times from the USB port but again the same problem! I can use only the wireless charging but that is not acceptable in a phone of this price; I won't buy Samsung again!
After trying a hairblower on low, and then a power off/on, I unplugged the charger adaptor from the outlet, and then pushed the port in and out of the phone a couple dozen times, moving it slightly sideways as I slid it in, a different way each time - up, down, then left, right. It finally is now charging.