Hmmm, could this be a problem with static vs dynamic IP address with your T-Mobile account causing T-Mobile to lose your server's whereabouts? I'm no expert here, but a few years ago I had a similar problem with Verizon and that's what it boiled down to. Verizon set a bit somewhere and the problem went away.

Since me dino posted, I ate lunch watching Unexplained Mysteries on the History Channel.
A tiime traveling episode of Capt. Kirk posing as William Shatner hosted an episode about curses that included cursed places for people to go.
Some could be selected for dinos but me not know.
BTW, my cursor is still working just fine.
Uh, whoa! Wait! Whatzit called? A CURSOR??!!!

Thanks, my issue is when using the internet provider T-mobile no one can
access the website server. Even T-mobile's employees can't reach the server.

for cheap you can get a Raspberry PI
use that for testing, off VPN

if it is compromised, easy to rebuild

Win10, Chrome
no issues

Working fine here (W7 on a vpn.)

Unfortunately, I can't reach my own business website due to a
technical problem between T-mobile and my hosting service.
This has been going on for over a month.
Neither T-mobile or the host has found the problem.
I wonder if they are even working on it.
Meanwhile I am losing access to ~50 million T-mobile
internet (potential) customers.