some cases, when you try to run any action (for example, Synchronization tasks, List/Relist/Revise/Stop actions) the error about M2E Pro Server connection fail can arise. You can get one of the following messages:
- "Please ensure that CURL library is installed on your Server and it supports HTTPS protocol. Also ensure that outgoing Connection to m2epro.com, port 443 is allowed by the firewall.";
- "Server connection is failed. Please try again later."
Below you can find the possible reasons for these errors and the ways on how to fix them:
1) Temporary Connection Problem - given that your server and M2E Pro server are physically 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 an ability to connect to our servers (s1.m2epro.com and s2.m2epro.com). Most probably this issue relates to DNS.
2) The Outgoing Connection was Blocked by Firewall - M2E Pro Servers (as of February 01, 2017 such servers are running s1.m2epro.com and s2.m2epro.com) must be in a list of allowed outgoing connections for ports 80 and 443. This prevents the outgoing connection from being blocked by the firewall. Therefore, M2E Pro will work properly.
3) 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 because of the data from your module is sent to M2E Pro server via the secure connection.
Note: In case you are using the Firewall, the incoming connection for cron.m2epro.com should be allowed too. Find more details about why Cron running is required in this article.