Work through these checks in order
Use a wall outlet you know works. Avoid diagnosing from a questionable extension lead, hub or public USB port.
Try a known-compatible cable, then a known-compatible adapter, so you can identify which component changes the result.
Look for visible lint, corrosion or damage. Do not insert metal tools or force connectors into the port.
Some devices pause or slow charging when very hot or cold. Restart the device and let it return to a normal temperature.
Intermittent charging at certain angles, visible port damage, liquid exposure or repeated accessory failures can point to hardware service needs.
Before an erase, restore or repair decision
Confirm what data is backed up, what a reset or restore will remove, and whether you still need access to account credentials or authentication methods stored on the device.
When professional service makes sense
Hardware damage, repeated power failure, liquid exposure, battery swelling, damaged ports, broken displays and problems that persist after low-risk software checks can require qualified inspection.