The Amazon Cloudfare service is used by several websites to protect them from DDOS attacks. It has blacklisted several BSNL IP addresses. This can randomly prevent you from accessing these websites.
When your Internet modem is turned on or restarts, it seeks a temporary IP address on a temporary lease for its WAN (internet) connection from the ISP. If the IP is in the Cloudfare blacklist and you try to reach a website protected by it, Cloudfare will not let your IP access it. In your browser, this will be shown as a ‘PR_CONNECT_RESET_ERROR’ error? There is no hacker meddling in your Net connection. It is Amazon and their stupid Cloudfare service.
The fix is to restart the modem. The modem requests another IP on a temporary lease and hopefully it is also not in the Cloudfare blacklist. If you do not want to get off your derriere every time this happens, then log in to your modem's configuration and find the option to restart (soft reset) the modem.