This error is due to either a licensing issue, missing Curl and CurlSSL, IP address mismatch, or misconfigured php.ini (/usr/local/lib/php.ini).
Licensing Issue
The plugin requires that you open outgoing ports 443 (SSL) and 80 (HTTP). This is required for the script to check against our licensing server to check for the validity for the license and continue to execute. Should you receive a License status Invalid message, please be sure to create a file called "unixyvarnish.license" under "/etc/varnish/", if it exists. Or create the file "unixyvarnish.license" from within the installation directory. In both cases, the file must contain the license key that you were provided upon signup. If the error persists, ensure that EasyApache has CurlSSL built into PHP.
Example:
[root@varnish varnish.unixy.net]# pwd
/usr/src/varnish.unixy.net
[root@varnish varnish.unixy.net]# cat -A unixyvarnish.license
Leased-cec3f81af739975b542ac688dasas30cc2$
[root@varnish varnish.unixy.net]#
Missing Curl and/or CurlSSL
You'll need to install these two extension via cPanel/WHM EasyApache. Also confirm that the following command is successful:
curl -vvv https://www.unixy.net
If you get the following error:
curl: (77) Problem with the SSL CA cert (path? access rights?)
You'll need to make sure the files /etc/pki/tls/certs/ca-bundle.crt and /etc/pki/tls/certs/ca-bundle.trust.crt exist on your server. If they do not exist, get your server management provider to complete the following two steps:
1) mkdir /usr/src/ca-certificates && cd /usr/src/ca-certificates
2) wget http://mirror.centos.org/centos/6/os/i386/Packages/ca-certificates-2010.63-3.el6_1.5.noarch.rpm
3) rpm2cpio ca-certificates-2010.63-3.el6_1.5.noarch.rpm | cpio -idmv
4) cp -pi ./etc/pki/tls/certs/ca-bundle.* /etc/pki/tls/certs/
5) confirm that curl -vvv https://www.unixy.net is now working as expected
IP Address Mismatch
Licensing of this plugin is per IP. Be sure you're accessing WHM using the IP that's listed in the product section in your Client Area.
Firewall Blocking
Be sure that outgoing ports 80 and 443 are open in the firewall
If none of the above fixes has resolved resolve the issue, open a request and post the output of these commands:
1) cat -A /usr/src/varnish.unixy.net-1.8.*/unixyvarnish.license
2) /usr/local/bin/php -i|grep -A12 cURL
3) curl -vvv https://www.unixy.net/
4) cat /usr/src/varnish.unixy.net-1.8.*/error_log