Troubleshooting

I can't hear anything in my DAW

Check in this order:

Is a MIDI destination connected? Settings tab → MIDI Devices — you should see a green CONNECTED box naming your device.
Is the DAW track armed to receive MIDI? Most DAWs require you to arm a track before they listen to input.
Is the DAW track receiving from the right source? The DAW's MIDI input dropdown should list Mobile MIDI (by the transport you chose).
Try a different transport. BLE can be flaky; USB is the most reliable test.
Check the MIDI activity indicator. On Mobile MIDI's app bar, the green music-note icon should flash when you play. If it doesn't flash, the problem is Mobile MIDI's side. If it flashes but the DAW is silent, the problem is the DAW's side or the connection in between.

My Mac doesn't appear when connected over USB

Almost always one of these three, in order of likelihood:

You haven't enabled the iPhone in Audio MIDI Setup. macOS discovers the phone but leaves its MIDI ports switched off until you say otherwise. Open Audio MIDI Setup → Window → Show MIDI Studio → select your iPhone → click Enable. Full walkthrough in Connecting to your DAW.
The cable is charge-only. It will power the phone and carry no data, which looks exactly like a software fault. Swap the cable before investigating further.
You're looking at the wrong thing. USB destinations appear under AVAILABLE in the MIDI Devices section, labelled USB, below the Presets section of the Settings tab. SCAN BLE will not find them — that button only searches Bluetooth.

Also worth trying:

Tap the ⟳ refresh icon in the MIDI Devices header. The list normally updates by itself, but this forces a re-check.
Rescan MIDI in Audio MIDI Setup's MIDI Studio window.
Unlock the phone and tap Trust if prompted — a locked or untrusted phone exposes no MIDI ports.
A different USB port, especially if you're going through a hub or dock.
Unplug and replug.

I tapped a device and it disappeared from the list

That's what success looks like. The AVAILABLE list only shows destinations you are not connected to, so your device moves out of it and into the green CONNECTED box at the top of the MIDI Devices section.

Scroll up slightly if you can't see it. If instead you see a grey box reading "Not connected", the connection didn't take — try tapping the row again.

Bluetooth MIDI won't connect

Make sure Bluetooth is on in iOS Settings.
Make sure Mobile MIDI has Bluetooth permission (iOS Settings → Mobile MIDI → Bluetooth).
Pair the devices via the app's SCAN BLE button, not via iOS's Bluetooth list (BLE-MIDI pairing is in-app).
Toggle Bluetooth off and on if a device used to connect and no longer does.
Reboot both devices if all else fails — BLE stack bugs are rare but real.

Face / hand tracking says "unsupported"

Face tracking requires a TrueDepth front camera (iPhone X or newer).
Hand tracking works on any iPhone with a front camera, but performance varies.
If the device technically supports it but tracking is unreliable — improve lighting, simplify the background, hold your hand or face at a comfortable distance.

Notes are stuck / playing forever

Switch template chips while holding a note — Mobile MIDI should send note-off, but occasionally the DAW-side state gets out of sync.
Fix: in the DAW, send an All Notes Off (most DAWs have a panic button / panic MIDI command), or disconnect and reconnect the MIDI device.
If it's happening reliably on one surface, file a bug via the contact email.

The app drains my battery

Mobile MIDI runs an active sensor pipeline, camera (if tracking), and Bluetooth radio. All of that uses power. Tips:

Turn off sensors you're not using — STOP the motion card, and remove catalog sources you added but aren't playing.
Close the Tracking tab when you're not using face / hand tracking.
Use USB MIDI when you can — it also charges the phone.

The UI stutters

Close background apps.
If you're on an older device, reduce the number of active sources. Too many continuous sources can overwhelm the render loop.
Report the device model and what was running — this is probably a performance bug we can fix.

Still stuck?

Email mail@aaad.am with:

iPhone model and iOS version
The exact steps that trigger the problem
A screenshot if applicable