Hi David,
I also have the same problem. Hosting a game works fine but Garden Ops always doesn't work. It usually connects to other players for a second in the lobby but then I'm kicked out every time, before the match starts. The message on screen says to check the internet connection but I know that's fine because Multiplayer works fine. I'm using PS4 with NAT2 connection.
I have seen several other reports on this forum from users with PS3 as well as PS4 versions all having the same connection problems with Garden Ops.
Please can you raise this higher for investigation? Thanks!