Trouble with multiroom music on Echo

[convergent]

I am new to Echo, and running into some weird problem with multiroom music.  I started with a Dot in my home office upstairs, connected to a Bose system by wire.  Loved it.  Then bought an Echo for the Kitchen, and tried multiroom playing of Spotify.  Seemed to work fine.  Next, I got another Echo for the Family Room, and added it to the Everywhere group.  Now the multiroom playing seems to be pretty inconsistent.  In an hour of fiddling with different music requests, I got one of the following results.  I usually say something like "Alexa, play music by INSERT_BAND_NAME on everywhere".

• It says OK, and plays as expected on all speakers
• It says OK, and then plays nothing
• It says OK, and then plays on the other speakers, but not the one that I spoke the command into
• It says that it can't find the group called everywhere

These random results can occur with the same spoken command, and on any Echo device.  I deleted the Everywhere group and created one called Downstairs, with just the two Echos in it... Family Room and Kitchen.  I get the same inconsistent result.  Its bad enough to be nearly unusable. 

The network is running on a NetGear Orbi connected to gigabit fiber Uverse.  In the house are a lot of other devices - Hue Lights, Samsung Smartthings Hub, Apple TV, Roku, Firestick, Chromecast, Ring Doorbells, Harmony Hub/Remote and lots of smart switches, bulbs, etc..  Everything is pretty much working on a consistent basis except this odd behavior with multiroom music.   

Anyone else having good or bad results with this?  I'm wondering if I should maybe give Google Home a try. 

[cdnirene]

Try this: When you finish listening to music in a session, say “Alexa, stop Everywhere”

Next time, make sure you ask it to play Everywhere and then stop Everywhere.

[convergent]

Thanks, I'll try that.