The issue here is that the printer is always connected to the Mac via a usb cable.  
but at the same time, the Dymo Connect software needs to link to their cloud service for it to work.  
if I take the Mac and Dymo home (normal home broadband and wifi) all works perfectly. 
at work- the Dymo stays offline in the app and I can’t print.  This is on my office Meraki network, but we don’t know how to overcome the block.