what I found with Amazon Echo after some testing: sometimes it connects fine, but doesn’t start playing as mode of the bluetooth connection is „source“ and not „sink“. This is due to the fact, that the Echo can be sink and source for bluetooth (and Max2Play also allows Streaming from a smartphone). Maybe the Pi decides by throwing a coin during connection which mode is used and you were unlucky in all your attempts…
Now how to resolve the issue: the bluetooth mode can be changed on the fly with an easy command for the Amazon Echo as user pi on console with
pacmd set-card-profile 2 a2dp
Where „2“ is the index of the card and „a2dp“ the prefered mode to send bluetooth to the Echo speaker.
Easy fix for you: I added a patch to the current BETA of Max2Play, that always chooses the bluetooth speaker mode for Amazon Echo. You should try this. At least after 1 minute of playback it will change to play on the Echo.