Try a reboot of the router.

Then set up the surround speakers as a separate room first, and them add them as surrounds. This seems to have worked for others, but I’m not sure why.

Finally, try adding the amp.

If you’re looking for help from Sonos directly, I would recommend that you submit a system diagnostic within 10 minutes of trying to add those devices, and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, there are more options available beyond just the diagnostic analysis. 

Thanks for your help. I followed your prescription but it didn’t work. I send a diagnostic to Sonos with id 1343829095. After the installation failed again 

hopefully a moderator is able to help me further. 
 

Sorry it didn’t help, I’ll keep my eyes on the thread to see what a moderator says. 

Hi @CoenSanderink,

Thank you for reaching out to the Sonos community and for your detailed post describing your concern. Let me help you with this.

The diagnostic shows that your Sonos Beam is detected as a dropped room and getting low wireless signal strength from the router. This could be the reason why you can’t add your rear speakers and sub in a home theater setup. Also, detected interference in your wireless network that may be caused by wireless congestion or low wireless range.

Let me suggest the following steps to see if this would work for you.

1. Reboot your Sonos Beam
   • Unplug your Sonos Beam from the power
   • Wait for 30 seconds before you plug it back in
   • Check on the Sonos app is your Beam is showing
   • Try to add your rear speakers as surround and add your sub
   • If the issue is the same, proceed to the next step
2. Sequential reboot to refresh your network and all your Sonos devices connection.
   • Unplug your network devices (modem, router, any wireless access points on the network) from the power and wait for 60 full seconds before you plug it back in.
   • Once the router is back online, unplug all your Sonos devices from the power. Please wait 15 seconds before you plug back them back in.
   • Force close the Sonos app from your iOS or Android device.
   • When the status light on your Sonos speakers are solid white, get back on the Sonos app and check if you're connected.
   • Check the status lights on your Sonos speakers, they should have solid white light an indicator that your Sonos is connected.
   • Try to add your rear speakers as surround and add your sub
3. Hardwire one of your speakers to your router.
   • Try to add your rear speakers as surround and add your sub

Let us know how you get on with the advice above. Please run another diagnostic report and include the confirmation number in your response.

Dear @Rowena B.,  

Thanks for your help. I followed your steps. Without succes. In addition I did the following

• changed the channel of Sonos from 11 to 6
• created a seperate vlan only for Sonos.
• wired the beam.

The installation fails. But after failing the speakers shown in the installation as speakers not as ?. The sub can be added successfully according installation ones but was not able to repeat.  But both rear and sub were not working according the ‘test’ serie on Netflix. 
 

send a report: 815875512

Hi @CoenSanderink, 

Thanks for your response and for submitting another diagnostic.

Upon checking the report, you have added the rear speakers as surround but not getting a signal from your Beam for the WiFi. Let me guide you on this.

• Enable WiFi on your Sonos Beam
  • Enabling the WiFi will broadcast the signal to other speakers in your home theater setup.
  • In the Sonos app, tap the Settings > System > Tap the name of the room (wired speaker) > Under Products tap the model of speaker > Select Enable WiFi
  • Test audio playback
• Add Sonos Sub
  • In the Sonos app, the Sub will appear in the System tab, tap to select it to associate it to your Beam.
  • Test audio playback

If the issue is not fixed, I recommend contacting our phone support for more in-depth troubleshooting steps. Please let me know if you have any further questions or concerns, we'll be glad to assist you.

That worked!!! I first had to add the speakers with the WiFi disabled on the beam. Than enable it. Hard close the Sonos app. Add the sub. And it worked!

Thanks for your support @Airgetlam and @Rowena B. 

Hi @CoenSanderink, that’s great! Thanks for your response and for updating us. I'm glad that it worked. Please feel free to reach out in the future if you have any other questions. You're always welcome here in the community.