Why wont my owlet connect to the internet?

Hello r/homenetworking,

I have an Owlet smartsock2 baby monitor that is used to monitor a newborn's pulse oximetry reading to detect hypoxia secondary to suffocation or other breathing issues. It was connected to my home network via a tplink archer c7 router a couple years ago when my first child was born and worked without issue. We stopped using the monitor when my first child turned 6 months old and it was carefully stored away. My wife is due with our second child any day now and she has tasked me with getting it working again. Owlet has since updated their smartphone app and I cannot get it to connect to my network despite hours of tech support with owlet customer service. The warranty is one year so of course they are not particularly interested in helping us get it working. Their manager is scheduled to call us back and I am hoping to speak with a software engineer or developer in attempt to either get the new app working or perhaps get an older version of the app that might work. As a hail mary I am reaching out to you guys to see if there's anything within my network that might be hindering the device setup. I am sure that their customer service will try to say that my network is the problem.

I have very little networking experience so I will attempt to explain the connection process in laymen's terms. The base of the monitor is a wireless networking device with its own SSID. The setup process requires the phone with the app to be on the same 2.4ghz network to which the base will be connected. Following the setup wizard links the base to the 2.4ghz home wifi and then tries to get the app to recognize and register the monitor base station through what I assume is WPS connection. In my conversations with tech support we ensured that the base was connected to the 2.4ghz band of my router and that the base firmware was up to date. I also made sure the 2.4ghz band was in mixed bg mode and not bgn per their recommendations. I have combed through the router settings looking for anything obvious, but again the monitor worked fine on the same network two years ago and as far as I can tell the only things that have changed are the app and our cell phones. I've tried disabling the wpa key and firewall with no success. Any ideas or does this sound like an issue with the app? Thank you for your help.