Because the backend execution time is too long and the front end does not wait, a 504 error is prompted.
504 error is caused by a limited latency and timeout setting on your CDN server.
504 indicates that the front end does not wait to be aborted, but the front end does not work. The back end should be normal.
502 error indicates that the backend does not respond, but the backend does not. If the frontend does not exist on your computer C: code in the \ windows \ system32 \ drivers \ etc \ hosts file (50.158.99.88 is the IP address corresponding to the domain name, cnblogs.com is your domain name)
50.158.99.88 cnblogs. com50.158.99.88 www.cnblogs.com
In this way, your browser can be forcibly executed on the backend server instead of using the front-end CDN server.
Force your browser to run on the backend server instead of using the front-end CDN Server
