Can't login to Ring App when using mobile hotspot

Starting from about two months ago, I am no longer able to log into my Ring app (on my android phone) when I am connect to my cell data hot spot. I have a RV, and in my RV I use some LET router with ATT and or Verizon's hotspot plan. Whenever my phone is connect to internet via that hotstpot, I am not able to log in or load the Ring app. It just keep spinning. The internet connection is absolutely working fine, as my phone can use other internet services (like YouTube, various web pages, etc), and I have disabled my phone's mobile data connection to verify that the hotspot connection itself are working fine. The app just couldn't load. If I switch to use my own cell phone's mobile data, it will work. I think (though I am not 100% sure), it is because the app was trying to decide my location via internet connection, because when this problem first happened, the app will say it can't load locations, something like that. Very frustrated about this.