I had the same issue, I tried everything else here. I ended up just needing to make sure I was broadcasting my WiFi SSID, and not hiding it. I was then able to get the soundbar to connect without an issue.
I have had this soundbar for about a year and a half.
HW-MS650 Sound+ Premium Sound-bar
i just realized my Warranty service ran out late last year.
I also can not connect via Wi-Fi, either through the App, or through my TV, Samsung QN55Q7FAM, by no means a cheap TV.
I was successfully able to have my sound bar connect via Wi-Fi one time, and then gave the same message of “unable to connect to Internet” or some other random garbage. It has not been able to connect since then.
I have attempted EVERY suggested troubleshooting addressed in this thread multiple times. My Soundbar will not connect, will not update.
I am am beyond disappointed there is no true and realistic work around that has been directed by Samsung. If there is, please direct me to it!!!!