Reimport Activity to Garmin 5x when deleted by accident

Hi Together,

today I deleted an activity by from my watch by removing the *.fit file from /GARMIN/Activity.
Is there a way to copy it back to my watch so it's seen in the protocol section and under "Last Activities"?

I downloaded the original .fit file from connect.garmin.com via "Export Original".
Tried out to copy this *.fit file to the "/GARMIN/New Files" section but it's not copied back to "/GARMIN/Activity".
Any idea how to import it back on my watch?