Hi @POWVorti, welcome to the Sonos Community!
This error is usually caused by network issues, so first I would recommend you reboot your network and Sonos system. You’ll want to reboot everything by powering it off for around 1-2 minutes in this order:
Router → Additional networking equipment → Sonos speakers → Controller running the Sonos app.
Once you’ve done that, check if you are still receiving Error 701. If the error persists, please check the steps in our article for reducing wireless interference, as well as changing the wireless channel of your router or the SonosNet channel if you have a wired device.
If none of the above steps help, please reach out to our support team for further troubleshooting. They can take a diagnostics of your system and have the tools to assist you in resolving this.
I hope this helps!
Thanks for your answer. After I contacted your colleagues I found out, that my Adguard Server caused the problem. It seems that there is something blocked in communication that should not be blocked. After disabling it, I am able to play songs again.
When I find out, what URL caused the error, I will post it…
My system suddenly blocked URLs looking like this:
rr5---sn-4g5edndk.c.youtube.com
After disabling this URLs from the block list I can use my Adguard system again.