Error starting domain: internal error Network 'default' is not active.

So here is how to fix that:

sudo virsh net-start default
sudo virsh net-autostart default

Details:

Error starting domain: Requested operation is not valid: network ‚default‘ is not active

Traceback (most recent call last):
File „/usr/share/virt-manager/virtManager/asyncjob.py“, line 91, in cb_wrapper
callback(asyncjob, *args, **kwargs)
File „/usr/share/virt-manager/virtManager/asyncjob.py“, line 127, in tmpcb
callback(*args, **kwargs)
File „/usr/share/virt-manager/virtManager/domain.py“, line 1355, in startup
self._backend.create()
File „/usr/lib/python2.7/dist-packages/libvirt.py“, line 1029, in create
if ret == -1: raise libvirtError (‚virDomainCreate() failed‘, dom=self)
libvirtError: Requested operation is not valid: network ‚default‘ is not active

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