Why did the site stop opening on a PC, but it opens without problems from a laptop and phone?

Question

Domain Name System

Good afternoon! Your help is very much needed.
One site (donationalerts) stopped opening for me, and it used to work with a bang and all its services for streaming in OBS, but at one point it started to load too long, and all its services stopped working, I thought it was a problem on the side of the site, but as it turned out - no. If you enable VPN in Opera, then the site enters without problems, and the site either takes a very long time to load, up to 15 minutes and it is impossible to do anything on it, or it gives an error 503. The site does not work in all browsers. Internet through a router, I tried to insert the cable directly into the PC - the problem remains. Moreover, from the phone via Wi-Fi from the same network, the site comes to the site without problems, I tried to plug the Internet cable into the laptop - I also went to the site, but from the computer - no. Removed the antivirus, cleaned the cache, cookies, dns, checked with Cureit, Malware, reset the network, registered Google DNS, hosts is clean, the router rebooted. Nothing helps.
Technical support advised to register the IP to their site in hosts, registered - it worked, it enters the site, but only for the browser, and the OBS program on the PC that uses the services of this site does not display their widgets and services, as if it was closed on the PC itself access to the site, although it goes to the site from the phone without problems and if you use a VPN, you can also use it from a PC, but the point is to use the site’s services for streaming in OBS, which do not work due to the inability to connect to the site. The provider says: "Unfortunately, this indicates a difficulty on a particular device.". I really need your help if you know. In advance, a huge, human thanks!

Answer 1

If the entry in hosts helped, then DNS is naughty. Change the DNS server on the PC or on the router, check which address the site is currently resolving to, make Wíreshark dumps to understand the source of the problem.
For example, my provider breaks into my traffic, trying to insert advertising, replaces dns requests, and blocks other people's dns servers. Perhaps you are in a similar situation.

Answer 2

Perhaps this OBS uses its own list of DNS servers that have suddenly become unavailable.
Or the provider intervenes, replaces.
You can try to track it through the command tcpdump -nni any port 53.
But to do this, you need to find and download tcpdump.exe, and you will not immediately understand its output ...
While OBS is running, you need to look at which IP addresses DNS queries go to and what answers come.

Answer 3

To begin with, check the site resolution through nslookup. Next, see which dns is responsible and the reason for the site block.
If the PC is Windows, then defender or a third-party antivirus can block.