My clients have transferred just fine- today and earlier.

Are sure that you have the assets in ProSeries itself or are they in FAM for 2017?  If they were in FAM in 2017 and you imported them into 1120S in 2017, they will not transfer with Proseries.  They are stuck in FAM and you must use FAM again in 2018.

If you are sure they are in Proseries, I would delete the file, run update, reboot the computer, and try to transfer again.

If that doesn't work, you will probably need to call support.