DNS problems on the server

The company applied for a fixed IP address from China Unicom, and then set up a website server in its data center. This server requires its own DNS to access the internet. after The DNS is configured on the server (centos, there is no problem with website access. but I used file_get_contents and other methods on this server... the company applied for a fixed IP address from China Unicom, and then set up a website server in its data center. This server requires its own DNS to access the internet. after The DNS is configured on the server (centos, there is no problem with website access.
However, if I use file_get_contents and other methods on this server, an error will be reported.

PHP Warning: file_get_contents (): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolutin

I'm sure it's a DNS issue! How can this problem be solved? Find China Unicom?

Reply content:

The company applied for a fixed IP address from China Unicom, and then set up a website server in its data center. This server requires its own DNS to access the internet. after The DNS is configured on the server (centos, there is no problem with website access.
However, if I use file_get_contents and other methods on this server, an error will be reported.

PHP Warning: file_get_contents (): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolutin

I'm sure it's a DNS issue! How can this problem be solved? Find China Unicom?

Restart Apache after modify/Etc/resolve. conf