Mobile internet doesn't work on browsers with VPN turned off, but it works in some apps, and works via Wi-Fi in all apps

I cannot use any browser with a VPN turned off using mobile internet, but I can use other apps, such as BBC or Viber. I also can access the internet via Wi-Fi with a VPN turned off. What I have tried: - I have reset APN settings many times, but it will not work. - I cannot turn off the proxy because there is no such option. The proxy section is blank. When I fill in the blank with some random letters, and then blank it again, the internet begins to work, and after a few searches on the browser stops. - Actually, when I change some other sections of APN the internet starts working, but then stops. - When I put a SIM card from a different provider into my tablet, it worked. And when I put my SIM card into another device, it also worked on that device. - I called the company for help. They say that my APN settings were out of order. They sent me new ones. That also didn't solve the problem. - I have even reset the tablet to factory settings. To my chagrin, it hasn't worked. I am clueless about whether or not the problem is with the tablet or the mobile data provider. Tell me please what is wrong.