Interestingly, this just started happening to me with one of my two Seestars. Actually, I think it's the same issue.
I have an iPhone 15. App sees the Seestar via Bluetooth, offers to connect via Wifi, iOS asks me to join network. It joins but then it just sits there indefinitely "Connecting to the Wifi of your Seestar". I also tried connecting to the Seestar network before starting the app. Same thing.
I am able to connect the Seestar to my laptop and it mounts properly as a drive, and I was able to copy things off of it using a USB cable. But I can't connect from the phone app and do anything with it.