We are experiencing a similar issue.  We are on a wired corporate LAN. Meaning that the connection is solid.    Seems like the issue can be worked around if you can get another email to play and then come back to the broken one.  What could the problem be?

​@Alycia408628026 ​@Casey_H I haven’t heard about anything like this, but if you are both experiencing this, it’s important that you log a ticket about it as it may be an emerging issue and the fix would more quickly get to you when it is resolved. 

We’ll keep our ears to the ground and post here if we hear anything similar. 
Keep us updated about what you’re experiencing.