If your domain name has been successfully submitted to the white list, but the record prompt page still pops up occasionally when accessing, and your server system is Linux, you need to enable the PMTU function.

Turn on using the following command:

 echo1>/proc/sys/net/ipv4/ip_no_pmtu_disc

This setting takes effect temporarily. After restarting the system, it becomes invalid. Just write the above command to the end of the/etc/rc.local file, and the restart will still take effect.

Or run directly: echo 'echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc' >>/etc/rc.local