Just got an ARC and 2 One SLs as surrounds. The Arc is connected via Ethernet and the SLs via WiFi.
The SLs keep disappearing from the app and trying to set them up as surrounds shows an error on the app and then presets them as connected. When trying to play surround move or to calibrate true sound the surround speakers do not respond or cannot be found. The WiFi reception near the speaker is very good.
Diagnostic number: 1562118009
Thanks for helping, this is highly frustrating.