Issues with M2E Pro Server Connection

In some cases, when you try to run any action (for example, Synchronization tasks, List/Relist/Revise/Stop actions) the error suggesting to impossibility of M2E Pro Server connection can arise.

The text of such errors is like:

  • "Please ensure that CURL library is installed on your Server and it supports HTTPS protocol. Also ensure that outgoing Connection to, port 443 is allowed by firewall.";
  • "Server connection is failed. Please try again later."

Below you can find the possible reasons of such errors and the ways to fix them:

  • Temporary Connection Problem - as physically you server and M2E Pro server are placed in a distance, the temporary failure of connection can occur. Such type of problem does not have a particular solution and just needs some time. So you can wait a bit and run the action again. But you can also contact your hosting support and ask to investigate why your server lost ability connect to our servers ( and Most probably this is issue related to DNS.

  • The Outgoing Connection was Blocked by Firewall - the M2E Pro Servers (on July, 20, 2015 such servers are running and must be in a list of allowed outgoing connections for ports 80 and 443. Thus firewall will not block the outgoing connection from your copy of Extension, so M2E Pro will work properly.

  • CURL Library is not installed on your server or it does not support HTTPS Protocol - CURL Library ought to be installed/updated on your server and it has to support HTTPS Protocol. Support and availability of HTTPS Protocol are obligatory as data from your module sends to M2E Pro server only under  secure connection.

Note: In case you are using a Firewall, the incoming connection for should be allowed too. You can find detailed information why Cron should be allowed following these links: