Sonos App not seeing system after using Alexa

Hi everyone, 

At home we have a system comprised of:

1 x Arc

1 x Beam

1 x Play:1

1 x Play:5

All have been working as intended previously, and even after we first setup Alexa the system continued to work fine both via voice commands and through the Sonos App for a while. Recently though, it seems that the Alexa app is somehow stopping the Sonos app from seeing our speakers, as we can continue to control them via voice commands but the Sonos app consistently gives us the message “Unable to connect to Sonos”. Sometimes turning our wifi router off and on works, sometimes just turning it off and on in our iPhone device settings seems to reset things, but only temporarily and we then have issues adding things to the queue via the Sonos app. 

Things we’ve tried:

• Following the app troubleshooting process (turn off all speakers, then back on, turn off router, then back on, discover devices etc. - This has limited and very temporary success)
• Deleting and re-downloading the Sonos app
• Reconnecting the speakers to our network
• Swiping up (on iOS) and quitting the Alexa app to make sure it’s not working in the background of any devices during all of the above.

I’m running out of ideas short of removing the speakers from the Alexa app and trying a similar process from that end but wondered if there was a more obvious (to those in the know) cause or solution for this? One possibility I thought of with my limited knowledge was if the devices are switching between the 2.4/5ghz channels on our router as a result of different types of commands would this create an issue?

Thanks in advance for any help, we’re losing patience trying things that are proving to be dead ends!

(All devices, firmware, software, and apps are up to date with latest versions available)