I also had this same issue on a 2023 GM Blazer. I have an unlimited data plan with on-star. Wi-Fi wouldn't work. while doing a Wi-Fi search with phone or laptop I would see the cars Wi-Fi name listed, I could hook up to it, but underneath it said internet not available. my apps on my cars audio system like Spotify or my weather app wouldn't work either because it didn't have an internet signal. I also got on-star on the line and went through all the hoops. turn-off Bluetooth to phone. let them send signals, turn off car, get out of car with key fob, step away from vehicle. get back in. turn car back on after a few minutes etc...
Nothing worked. they said they needed to start a ticket for their technician team, and they would call me back in 3 to 5 business days.
I ended up researching how many fuse boxes my vehicle had and what fuses controlled what device etc... i found 3 fuses in the fuse box that's under my dash console area, that controlled communication, radio, and something else that sounded like it could have played a part to the Wi-Fi and I made sure the car was completely off, pulled the 3 suspicious fuses out. waited about a minute and put them all back in. I guess this reset something because my Wi-Fi instantly started working again when i turned the car back on.
I don't know if this is the fix, but it worked for me.
hope you guys figure it out. Cheers!
PS. before I put all 3 fuses back in, I made sure they weren't blown and needed replaced first.
