Please help, having issue with sub-mini!

I’ve had a Sonos Arc for a long time and love it. For Christmas my wife got me a sub mini to add to my system. I went through the set up process but the sub mini despite assigned to my arc kept showing up as “Not connected”. Tried factory resetting the sub and still kept getting the same “not connected” error. Today I woke up and decided to just create a whole new Sonos system, by factor resetting my arc and sub. I added the sub to the system first without issue, and then added the arc, no issue (see pic 1). Then I assigned the sub to my living room/arc (see pic 2). After that I went back to the previous screen and now the sub is once again being shown as “not connected” (see pic 3). Looking for any assistance if anyone has been able to trouble shoot this problem. FYI: I’m in an apartment with provided WiFi, my apartment has its own network, but I don’t have a physical modem that I can plug into/reset.