Why are some sites not loading via wifi?

Question

WiFi

In general, I use a wifi router with a 4G modem, everything worked yesterday. And now I have already tried 3 different routers and all have the same problem. YouTube and Google search work fine, everything loads, and the rest of the sites are either wildly stupid or not loaded at all. And this is all when connected via wifi, both on a smartphone and on a laptop, the situation is similar. When connecting the modem directly to the laptop, there are no problems. Some kind of nonsense, tell me how you can solve it?
* Simka with an unlimited tariff for a modem.
** I connected the modem to my laptop and tried to distribute wifi from it, the problem is still the same.
*** The problem is the operator's ban on distribution. Unlimited tariff is not so unlimited. I flashed the modem in Hilink and fixed TTL on it, the problem is gone.

Answer 1

The cellular operator does not want you to distribute the Internet through a router. When work is detected through the router, the speed is cut. Solutions:
1) switch to another tariff plan without distribution restrictions; may be significantly more expensive.
2) switch to a less greedy cellular operator.
3) to deceive the operator with the settings of the router; for this you need a router with more or less smart firmware (dd-WRT, OpenWRT, Mikrotik), which allows you to change the TTL of packets; You can google the setup instructions.