Now I have problems with scanning the code again. And I don't know why few days ago I was in vr services app and changed device by mistake to standard cardboard. Since then cardboard does not accept QR code anymore. It constantly says it does not know the code.
I tried to make a new code but this was also not accepted.
I hope someone can help me with this.
Edit: problem solved. Installed another qr code reader. Then scanned the code and opened result with cardboard app. Done