Troubleshooting

Chrome blocked local network access

The page at droid.devpier.dev connects to the gateway on your own Mac. Chrome asks for permission the first time. If you denied it, the page cannot connect, and after a few failed attempts it tells you that Chrome blocked access to your Mac.

To allow it again:

1. Open Chrome Settings → Privacy and security → Site settings.
2. Find droid.devpier.dev and allow local network access.
3. Reload the page.

If you still cannot connect, use the local fallback page.

Port already in use

The gateway listens on port 7300 by default. If another program already uses that port, the gateway cannot start on it. Find the program:

lsof -nP -iTCP:7300 -sTCP:LISTEN

Stop that program, or start the gateway on another port:

android-emu-web --port 7301

The gateway puts the new port in the address it opens, so the page connects to the right port.

No emulator found

If the page says no running emulator was found:

• Check that an emulator is running: adb devices should list emulator-5554 or similar.
• Check that it was started with gRPC enabled (-grpc <port>). The gateway cannot read the screen of an emulator without gRPC.

You can also start a device from the list in the page. See Devices.

The gateway keeps running when no emulator is found, and prints the reason in Terminal.

If the gateway reports that the Android SDK, emulator, platform-tools or the system image is missing, follow the fix it prints. See First run.

“sdkmanager” is missing

An SDK installed by Android Studio may not include cmdline-tools, which provides sdkmanager and avdmanager. The gateway does not download it. Download Google’s command line tools from developer.android.com and unpack them so that this path exists:

<your SDK>/cmdline-tools/latest/bin/sdkmanager

The token has expired

The gateway makes a new token each time it starts. If you restart the gateway, a page that still has the old token shows that the token is no longer valid and stops retrying. Open the new link the gateway printed, or run the gateway again.

The page says the gateway or the page is out of date

• Gateway out of date: run the upgrade command the page shows. It is the same as the install command.
• Page out of date: force-reload the page with Cmd+Shift+R.

Wrong browser

The page works only in Chrome and Edge. In other browsers it asks you to switch and does not try to connect. See Browser support.

Use the local fallback page

The gateway serves the same page at http://127.0.0.1:7300/app/ (or the port you chose). Use it when the public page does not load or local network access was denied.

The screen stops updating

If the emulator exits or restarts, the page shows that it is disconnected. The gateway keeps running. When the emulator comes back, the page reconnects and the screen returns.