Hi @dasra23 ,
I’m glad that was useful. I am, unfortunately, not familiar with the Azure Dev Centers as I have never used them so I am unlikely to be able to help with specifics related to their configuration.
However, this error seems to require an ‘attached network’ and, looking at the AZAPI documentation it should be available as a data resource if it is attached: Microsoft.DevCenter/projects/attachednetworks. If it is not (which the error seems to suggest) then you are likely to be missing some configuration to associate the network with the project or DevCenter instance. Which in turn seems to be managed by this resource:
Microsoft.DevCenter/networkConnections
Hope that helps a little further