PST Capture Console Import Error

Hello, we are beginning a client migration this weekend and I'm testing the PST Capture Console tool as recommended by O365. Communications have been set up properly and test good however after selecting the pst file to import and beginning the process. The import fails 15 minutes in with an error of "the agent was timed out in responding to the transfer request". Does anyone have any experience with this?

Best Regards, BillG