01Why the alert pops up
"This accessory may not be supported" appears when your iPhone checks the cable or accessory you've plugged in and doesn't like the answer. It can't charge or talk to the accessory normally, so it warns you instead.
On Lightning iPhones (iPhone 14 and earlier), every genuine cable and accessory carries a small authentication chip. The iPhone asks that chip to identify itself. A counterfeit chip, a chip that has failed, or a broken wire stopping the reply all trigger the same alert. USB-C iPhones (iPhone 15 and later) use standard USB-C rather than Apple's chip, but you can still see the message when a cable is damaged, the port is blocked, or the accessory needs something the iPhone can't provide.
| When you see it | Most likely cause |
|---|---|
| With one cable, never with others | That cable is damaged or not certified |
| With every cable you try | Lint, moisture or damage in the iPhone's port |
| Only with one charger or car port | The charger or port can't supply proper charging power |
| Only with a dock, adapter or hub | The accessory isn't supported, or needs more power |
| Right after an iOS update | An older or uncertified accessory no longer passes the check |
| With nothing plugged in | Debris or moisture is touching the contacts |
02Six fixes to try, quickest first
-
Unplug, wait, plug back in
Dismiss the alert, pull the cable out, wait ten seconds and push it in firmly until it seats flush. A plug that's half in can fail the check.
-
Swap the cable
Borrow a cable that works on another iPhone. If the alert disappears, your old cable is the problem and no setting will fix it.
-
Swap the charger
Plug into a wall charger instead of a car port, keyboard, monitor or power strip. Some USB ports are meant for data or tiny gadgets and can't charge a phone properly. A 20W USB-C charger covers any iPhone.
-
Clean the port
Turn the iPhone off, look into the port with a flashlight and ease out lint with a wooden toothpick. Don't use metal, and don't blow into it.
-
Restart and update
Restart the iPhone, then check Settings > General > Software Update. Updates sometimes add support for newer accessories.
-
Test with the accessory's own cable
For docks, card readers and adapters, use the cable that came with them and check the maker's site for a list of supported iPhones. If your model isn't listed, it may simply not work.
Some cheap cables let you clear the alert and carry on charging. That's exactly the kind of cable that can overheat or damage a port. If a cable triggers the warning repeatedly, bin it.
03Spotting an uncertified Lightning cable
If your iPhone uses Lightning, the cable needs Apple's MFi (Made for iPhone) certification to pass the check reliably. Knockoffs often work for a few weeks, then an iOS update or a failing chip starts the alerts. Here's what to look at:
- The packaging should carry the Made for iPhone badge. No badge, no certification.
- The Lightning plug on a genuine cable is one smooth, solid piece with evenly finished contacts. Rough edges, uneven contacts or a loose fit are warning signs.
- The price. Certified cables cost money to make. A three-pack for the price of a sandwich usually isn't certified.
- The behavior. A cable that charges, then throws the alert, then charges again is failing its check intermittently.
USB-C iPhones don't use MFi for cables, so any well-made USB-C cable works. Quality still matters: a poorly made cable can drop out mid-charge or get warm. See is it safe to use a non-Apple charger for the charger side, and how to spot a fake charger if the brick looks suspect too.
04The alert with nothing plugged in
If the message appears when the port is empty, something inside it is bridging the contacts. Usually that's packed lint, a crumb or a little moisture. Turn the phone off and clean the port gently. If it got wet, leave it to dry for a few hours, port facing down.
"Liquid Detected in Lightning Connector" or a USB-C liquid warning is a separate message. It means the iPhone has found moisture and is protecting the port. Apple advises against putting the phone in rice. Unplug, tap it gently with the port facing down, and let it air-dry.
If the alert keeps appearing on an empty, clean, dry port, the port itself may be damaged. That's a job for Apple or an authorized repair shop.
05Picking a cable and charger that won't trigger it
For an iPhone 15 or later, any decent USB-C to USB-C cable and a 20W or bigger USB-C charger is all you need. For iPhone 14 and earlier, use a certified USB-C to Lightning cable with a USB-C Power Delivery charger, which also gets you fast charging. Our "Slow Charger" explainer covers the other alert people see with cheap bricks.
Replace the part that failed the swap test. Check any Lightning cable's listing for MFi certification before you buy.
Questions people ask
Can I still charge my iPhone if it says this accessory may not be supported?
Sometimes the phone will charge after you dismiss the alert, but it's a warning sign. The cable or charger may be damaged or uncertified, and those can overheat. Switch to a known-good cable and charger rather than ignoring it.
Why does my iPhone say this accessory may not be supported with an Apple cable?
Genuine cables wear out too, usually at the plug where they bend. Lint in the port or an underpowered USB port can also trigger it. Try the cable on another iPhone, and try your iPhone with another cable, to see which side is at fault.
Does this accessory may not be supported happen on USB-C iPhones?
Yes, though it's less common than on Lightning models. On iPhone 15 and later it usually means a damaged cable, a blocked port, or an accessory that needs more power or a feature the iPhone doesn't offer.
Can an iOS update cause this accessory may not be supported?
It can. Updates can tighten how iPhones check Lightning accessories, so an uncertified cable that worked before may start failing. The fix is a certified cable, not rolling back iOS.
How do I know if my Lightning cable is MFi certified?
Look for the Made for iPhone badge on the packaging and buy from a seller who states MFi certification in the listing. A smooth, one-piece Lightning plug and steady charging with no alerts are good signs too.