What Does This Error Mean?

Wireless fast charging failing usually means the charger's power adapter is not providing enough wattage, or the phone and charger do not share a compatible fast-charge standard. Use the USB-C adapter that came with the charger — most require at least 18W.

Affected Models

Anker wireless chargers
Belkin BoostCharge Pro
Samsung 15W wireless charger
Apple MagSafe charger

Common Causes

Power adapter delivering less wattage than the charger requires — e.g., 5W adapter on a 15W charger
Phone and charger using incompatible fast-charge standards (Samsung EPP vs Apple MagSafe)
Thick phone case blocking the coil and reducing charging efficiency
Wireless charger temperature protection throttling output due to heat
Phone software update changed fast-charge compatibility temporarily

How to Fix It

Use the correct power adapter.

Wireless chargers require a USB-C adapter with a minimum wattage to unlock fast charging. A 15W Samsung wireless charger needs at least a 15W USB-C PD adapter. Using a 5W USB-A phone charger as the power source limits the wireless charger to 5W regardless of its rated speed.
Verify charger and phone compatibility.

Not all wireless chargers work with all phones at maximum speed. Samsung phones charge fastest on Samsung Qi2 or EPP chargers. Apple iPhones reach 15W only on MagSafe — Qi chargers cap at 7.5W for iPhones. Check the charger's compatibility list for your specific phone model.
Remove or replace a thick phone case.

Thick cases, especially leather or wallet cases, reduce the coupling efficiency between the phone coil and the charger coil. Remove the case and test whether fast charging speed improves. For cases thicker than 3 mm, even compatible wireless chargers default to a lower charge rate.
Ensure the charger is not overheating.

Wireless chargers have thermal protection that automatically reduces output wattage when the pad surface gets too warm. Move the charger to a cooler surface, keep it out of direct sunlight, and do not charge with the phone actively running navigation or games. Charging speed returns to full after the pad cools.
Restart the phone.

Occasionally a phone software state causes it to negotiate a lower wireless charging power level. Restart the phone, place it back on the charger, and check the charging speed indicator. System updates sometimes temporarily break fast charge negotiation until a second restart.

When to Call a Professional

Wireless fast charging issues are always caused by adapter wattage, compatibility, or heat. No hardware repair is needed unless the charger produces no output at all.