If you see one of these alerts, your iPhone has detected liquid in the Lightning port or on the Lightning cable or Lightning accessory. To protect your iPhone and the accessory, charging and accessory connection are unavailable until the Lightning port and the accessory are dry.

Charging not available: Appears if you connect your iPhone to a charger and liquid is detected.

Liquid detected in Lightning Connector: Appears if you connect an accessory to your iPhone that doesn’t charge your iPhone and liquid is detected.

If you charge your iPhone while the Lightning port is wet, the pins on the Lightning port or the cable can corrode and cause permanent damage or stop functioning, causing connectivity issues for your iPhone or accessory.

Although you shouldn’t charge your iPhone when it’s wet, you might need to in an emergency. If you reconnect your iPhone to the Lightning cable or accessory, you have the option in an emergency to override the liquid detection and charge your iPhone.

If you have a wireless charger, you can still use that to charge your iPhone. For best results, make sure that the back of your iPhone is dry before you place it on your Qi-certified charger. Learn more about wirelessly charging your iPhone.

If your iPhone or Lightning accessory is wet

Unplug all cables or accessories. Don’t plug them in again until they’re completely dry.

To dry your iPhone:

Tap your iPhone gently against your hand with the Lightning connector facing down to remove excess liquid. Leave your iPhone in a dry area with some airflow.
After at least 30 minutes, try charging with a Lightning cable or connecting a Lightning accessory.
If you see the alert again, there is still liquid in the Lightning port or under the pins of your Lightning cable. Leave your iPhone in a dry area with some airflow for up to a day. You can try again to charge or connect a Lightning accessory throughout this period. It might take up to 24 hours to fully dry.

Here are a few things not to do:

Don’t dry your iPhone using an external heat source or compressed air.
Don’t insert a foreign object, such as a cotton swab or a paper towel, into the Lightning connector.
Don’t put your iPhone in a bag of rice. Doing so could allow small particles of rice to damage your iPhone.

If your iPhone and Lightning accessory aren’t wet

If you see this alert every time you connect a certain cable or accessory, that cable or accessory might be damaged. Contact the manufacturer.

If you see this alert every time you connect an Apple Lightning cable or accessory, contact Apple Support.

Taken from https://support.apple.com/en-us/HT210424

For Samsung devices,

Last Update date : Aug 04. 2021

Samsung devices will not charge if moisture is present in the charging port when it is plugged in. This is a preventative measure added to avoid corrosion. In the event a charger is plugged in while moisture is detected in the charging port, a pop-up message will be displayed. You still be able to charge with a wireless charger on supported devices.

Please note: To avoid electric shock and damage to your phone or tablet, do not charge while it is wet or in an area where it could get wet. Do not handle the device, charger, or cables with wet hands while charging. Do not insert any object into the charging port. This can result in damage to the charging port.

Remove the moisture.

If you try to connect your phone or tablet to the charger while the charging port is wet, you will hear an alarm go off with steps to disconnect the charger. The alarm will continue to sound until the charger is disconnected. Gently shake the device to help remove water or moisture from the port.

Wait for moisture to evaporate.

Water will naturally evaporate from the charging port within approximately 1 to 2 hours. If any liquid other than fresh water enters the charging port of your device, rinse it in fresh water and dry it thoroughly with a dry, soft cloth.

Please note: Most Samsung tablets are not water resistant. Only Galaxy Active tabs can be exposed to liquids.

Use a wireless charger.

Wireless charging is not affected by moisture or foreign objects in the charging port. If your device supports wireless charging, you can try charging it that way. Make sure to thoroughly dry the device before placing it on the wireless charger.