I have the same problem. When I contacted support they first told me that I had too many rules set up. Then they told me that it was a problem with my hosting and I should call my host. I reminded them of the hosting requirements listed in the FAQ and asked them exactly what was required to get the software to work. They couldn’t tell me but instead referred me to the online documentation for WPRobot for help!
I’m not kidding! Here is a link to where it spilled over into the Warrior Forum: https://www.warriorforum.com/internet-marketing-product-reviews-ratings/234239-anyone-else-trying-use-multipress.html Please read this thread. It covers the problem extensively.
The WPRobot documentation was excellent and I learned a lot about WordPress but the solutions suggested there do not help with the Multipress problem because Multipress lacks many WPRobot features. For example, I think that our autopost problem might be resolved by WPRobot’s advice to select to run with the main cron instead of the WordPress cron but Multipress does not have the feature to select that.
I have spent a lot of time on this issue and my hosting has been great and worked on it with me but I cannot resolve the problem.
This is just my best guess but I believe the Multipress plugin conflicts with other plugins that rely on WP cron. Unfortunately those plugins include wp-database-backup and Google-xml-sitemaps, both of which I consider essential and very solid plugins.
I wish you luck in getting this resolved. If you do find a solution please post it here.
I hope you are running the trial version because they absolutely refuse to give any kind of refund.