Sheet don't show up when opening .mid from FL Studio 20.

Hi,
I was trying to export .mid from FL Studio and then open it in Musescore in order to have the sheet.
Unfortunately, when opening it with Musescore, it doesn't show anything new, except for an empty toolbar at the bottom.
Is there any known fix to this? Or something I should consider while exporting etc?

Thanks for any help in adv.
Clemens