Echo shows offline when I'm not on the wifi network

[Equinox]

Hi, first post and this might be the norm but I've asked Amazon directly and they missed the point. The echo connects to the network and works perfectly fine, for the first time I've been onto the Alexa app when away and the echo shows as being offline. Is this normal or should I be able to see the echo being online no matter where I am? Can't find the answer on google and Amazon replied with a response relating to having issues connecting the echo to a network.

[mike27oct]

I just turned off my wi-fi and used cellular to test your problem.  Either way, my devices that are online ARE shown as online in app's Settings.  When you get home be on your  and check settings, then turn off wi-fi and use your cellular to check settings.  Your results should be the same both ways as mine was.