the REST API encountered an error

i was trying to edit website theme files in wordpress interface but when i update it, it gives me this error.

Unable to communicate back with site to check for fatal errors, so the PHP change was reverted. You will need to upload your PHP file change by some other means, such as by using SFTP.

wordpress site health plugin gave me this error

The REST API request failed due to an error. Error: [] stream_socket_client(): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution stream_socket_client(): unable to connect to tcp://winnie-logistics:80 (php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution)

how to solve these errorrs?.