Did you wait until you got a GPS position before you started your activity? It is usually a GPS text or bar that turns green when you got a position. On rare occasions it can take very long time until you get a GPS position. I've experienced that after software updates, change to summer/winter time and when Garmin had issues with the expired EPO files.
I suggest that you restart the watch and start a new activity and test that it works after that.
I have a vague memory of some issue with the privacy zones that could cause the map to disappear. Privacy zones shouldn't have any affect while you are logged in, but if you are using privacy zones it could be an idea to temporarily remove any that could affect your activity.
Not that this is useful, but one of my friends has this going on too. Not sure to what extent he's troubleshoot-ed it, but it used to work, and since last week it the week before it doesn't show the maps. Distance is logged. he gets Green GPS at the start. He's got a Forerunner 235
I think it would be a good idea to post the FIT file in the forum so we can take a look at it. It is probably best to use the FIT file from the watch instead of exporting it from Garmin Connect since Garmin Connect isn't showing a map.
