I’m not sure if you found a solution but I connected by using the smart things app. Strange how it all worked out, but for the life of me, I couldn't connect to WiFi using the MultiRoom app. I installed smart things and it found my soundbar, then from there I connected to the Multi room app. I was trying to update my soundbar and that's how I accidentally got connected, using the article below for information. https://www.samsung.com/uk/support/tv-audio-video/how-to-update-your-soundbar-using-the-smartthings-app/ I hope that helps.
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