Cannot debug on device: connection refused

Unity Engine
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1

Hello, I am having trouble debugging my App on an Android device via Mono/VS on a PC.

  • Device: Samsung Galaxy S6 (SM-G920F, Android 7.0)
  • The device is properly connected to adb via WiFi, logcat works flawlessly.
  • Firewall and antivirus disabled on both, Windows PC and Smartphone.
  • The smartphone is in developer mode with USB debugging enabled and my app is selected as the debug target in the developer menu.
  • I verified multicast is working properly in my network.
  • PC and smartphone can reach each other (ping)
  • The device properly shows up in the IDEs Attach Debugger menu.
  • The build is a development build with script debugging enabled, device filter FAT, runtime .net 3.5 equivalent, backend mono

When trying to attach the debugger, the following happens:

  • Mono: Error-message “Could not connect to the debugger”. When attaching a debugger to Mono, the following Exception pops up: System.Net.Sockets.SocketException: ‘No connection could be made because the target machine actively refused it 192.168.1.136:56921’

  • VS 2017: Nothing happens. When attaching a debugger to VS, the following is printed to the output:
    Exception : Unable to start program ‘Unity’. Operation not supported. Unknown error: 0x80004005.

Please help, I already invested a lot of time into something that should be working from the start - this makes Unity unusable for me.

2

So this is funny, I left the PC in standby for 2 hours, and now its working, out of the blue, no changes done - what is this black magic? Were to many ports used up from trying to fix this all day? Please Unity, improve the error handling and give better error messages!

3

The issue appeared again after I switched the project to il2cpp - maybe this was the issue I had above because I did play with this setting before. I tried switching between il2cpp and mono three times, each time debugging the mono version worked, il2cpp never (fresh project). Can someone reproduce this?

Also: .net 4.6 + mono causes the app to crash on startup for me (I guess this issue: Unity Issue Tracker - [Android] Script debugging causes Android to crash on startup with .NET 4.6). This leaves me with the only option: .net 3.5 + mono…

4

Just in case, you didn’t see - https://docs.unity3d.com/Manual/AttachingMonoDevelopDebuggerToAnAndroidDevice.html

5

@Tomas1856 : thanks, all of that is properly set up, it’s not the issue. I am waiting for someone to reproduce the il2cpp debugging issue and will then file a bug report.

6

Same issue here… switching to mono backend allowed us to attach the debugger…