WP Mail SMTP Stops Working

I have changed my Hosting Server and WP Mail SMTP Stops Working;
i have checked and configured the settings of WP Mail SMTP.

but still its not working.
below is the Debug Data:

Versions:
WordPress: 4.9.8
WordPress MS: No
PHP: 5.6.39
WP Mail SMTP: 1.4.2

Params:
Mailer: smtp
Constants: Yes
ErrorInfo: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Host: server.synergyhomeopathic.com.
Port: 587
SMTPSecure: tls
SMTPAutoTLS: bool(true)
SMTPAuth: bool(true)

Server:
OpenSSL: OpenSSL 1.0.2q 20 Nov 2018
SMTP Debug:
2019-03-24 10:46:32 Connection: opening to server.synergyhomeopathic.com.:587, timeout=300, options=array (
)
2019-03-24 10:46:32 Connection: Failed to connect to server. Error number 2. “Error notice: stream_socket_client(): php_network_getaddresses: getaddrinfo failed: Name or service not known
2019-03-24 10:46:32 Connection: Failed to connect to server. Error number 2. “Error notice: stream_socket_client(): unable to connect to server.synergyhomeopathic.com.:587 (php_network_getaddresses: getaddrinfo failed: Name or service not known)
2019-03-24 10:46:32 SMTP ERROR: Failed to connect to server: php_network_getaddresses: getaddrinfo failed: Name or service not known (0)
2019-03-24 10:46:32 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

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