Cannot download maps via Wi-Fi

No idea. I get the same message (with latest installed beta). Maybe a Garmin server problem?

Same problem in Germany…

Use Garmin Express it's a giant update file at 19 gigabytes and will take around 25 minutes to update via Garmin Express.

We are talking about OM+ maps...

Same for me in Germany. Prior to update on latest firmware 15.31 I also got the error. Now, I sometimes get the error and in other tests I get the download display, but sometimes it stays at 0%, sometimes at 1% or a few more. But ultimately just stuck. I also sent a message to Garmin support. However, no reaction after a couple of days. 

Same here. I'm trying right now and after 15 mins I've downloaded 3% of about 1 GB.

The good news is that after about 1 hour I downloaded the map

Lucky you. For me it is still stuck... And I also tried multiple map locations to test whether it might be a location issue.

Tested again yesterday. Now it suddenly works for me again. I did not change anything on the device. So I do not know the reason, but obviously, I am happy. Maybe it was something on the service side. But it seems to improve quite a bit. My watch also crashes a lot less since the upgrade to 15.31. I read that other users have different experience. But quite good for me at this time.