Reasons and solutions for website failure to open

1: "You cannot access this page" appears because repeated login triggers the security mechanism
* Solution: Add /?cf=1 to the suffix when accessing the website to prevent repeated login . For example: https://www.baidu.com/?cf=1
2: Network speed problem, timeout or no response.
3: The website cannot be accessed or does not respond due to DNS, and the server connection times out (taking win10 as an example) :
Settings-Control Panel>Network and Internet>Ethernet>Network and Sharing Center>WLAN (TP-LINK, that is, your own wifi) >Double-click Internet Protocol Version 4 (TCP/IPv4) > Select "Use the following DNS server address" and enter dns, OK. After finally changing the DNS server address, it is recommended to clear the browser cache file. Processing method: Press "Windows+
R
" Shortcut key > Enter "inetcpl.cpl" > Press Enter > Press the shortcut key "Alt+D" > Check the cleanup item and continue with the shortcut key "Alt+D" > OK (cleanup is completed).
DNS:
Baidu: 180.76.76.76; 223.5.5.5 (standby)
Alibaba: 223.5.5.5; 223.6.6.6 (standby)