I get this error (Liquid detected in Lightning Connector:) after the iPhone X is done charging, the cable works fine in my iPad and doesn’t give me the error. My iPhone is dry and has never been in a dropped in water.

Hi Shebee2,

Thanks for using Apple Support Communities. Charging your device is definitely important. We see you're sometimes receiving an alert that liquid is detected in your iPhone charging port, and the cable works with your iPad. The resource If you see a liquid-detection alert on your iPhone was a good start.

Do you happen to have another charging cable available? Even if you've tested the same cable with your iPad, testing another cable with the iPhone might help in narrowing this down. If you continue to see the same alert, that's when you'll want to reach out to Apple directly: Get Support

Take care.