Echo Dot v3 always showing offline.

[Cbray37]

I've searched everywhere for a solution to this and tried everything I can find but to no avail !!
My Echo Dot v3 always shows as offline in the alexa app. This is both when set up on Iphone and Ipad.

Strangely my daughter was able to get it showing as online straightaway when she set it up on her phone. So there seems to be no problem with the echo dot or the wifi.

Any suggestions gratefully received :-)

Update

 By setting up a new amazon account and registering the echo dot with that account it is no longer showing as Offline.  I still need to get it working with the old account for using Amazon Prime music.