OmniPlan and Smartsheet


I need to upload some of my oplx to Smartsheet and Smartsheet has an option to import mpp. I export my oplx to mpp and when it gets imported into Smartsheet, the predecessors are gone and all the tasks are grouped under a single root task. Has anyone encountered this problem before and have a solution for this?

When I upload a non-OmniPlan generated mpp to Smartsheet, this problem does not exist. TIA!