In the latest versions of Litespeed server default settings for External Application Abort were changed. In result Litespeed server closes connection and synchronization is not completed successfully.
All users who had their Litespeed server upgraded recently started having issues in Synchronisation.
Cron Service is a predefined free service from M2E Pro that lets Users to not be nervous about Linux Cron job settings. The principle of it's work is based on the regular requests to a particular end point in Extension with further run of synchronization tasks at the moment of this connection.
In two words it is working in such way: remote Cron Service initialize a request to a particular end point of M2E Pro Extension with further disconnection from it's side. However, the PHP scripts should be running even after connection with Cron Service fails. But in some versions of LiteSpeed web-servers the default setting does not let the Cron Service to run synchronization after disconnection.
There are two ways to make M2E Pro Cron Service work correctly: