Add an article about using AdGuard VPN in problematic countries

Linked to #137

docs/general/vpn-issues.md

@@ -0,0 +1,32 @@
+---
+title: 'How to use AdGuard VPN in countries with Internet restrictions'
+sidebar_position: 10
+---
+
+In certain regions, such as China, Iran, and Russia, users might have problems connecting to AdGuard VPN. Here are the options that might help.
+
+## Accessing AdGuard VPN’s website
+
+If adguard-vpn.com is not accessible, use the mirror websites: [adguard-vpn.info](https://adguard-vpn.info/welcome.html) or [adguardvpn-help.com](https://adguardvpn-help.com/welcome.html).
+
+:::info
+
+To avoid potential phishing or malicious websites, only follow mirror links provided in this Knowledge base or by the AdGuard VPN support team.
+
+:::
+
+## Other useful tips
+
+- Always make sure that you are using the latest version of AdGuard VPN, as updates typically include vital fixes and enhancements.
+
+- Use AdGuard VPN’s full apps instead of browser extensions for a more robust and stable connection.
+
+- If you encounter problems connecting to a particular location, try connecting to an alternative one. If all locations fail to respond, restart the app to refresh the server list.
+
+- Try switching between mobile data and Wi-Fi: the problem may be network-specific.
+
+- If you use AdGuard VPN alongside AdGuard Ad Blocker on mobile, ensure that the *General* or *VPN* operating mode is selected in the app settings.
+
+- If you have connectivity issues, do not enable *Use QUIC* in *Advanced settings*.
+
+If all else fails, don't hesitate to reach out to our support team at [email protected] for further assistance.