[resolved] Building image, network lost during build

Running docker-ce on debian stretch, I’m building a docker image (which I’ve successfully built before, a few months ago).

The Dockerfile has 2 package download & installation steps, one to do some initial prep & the second to install around 50 additional packages - some from a 3rd-party repo & their dependencies.

The first package installation step works, the second one always gets to around the same step before something forces a network configuration, the docker container IP address changes, then both docker & the laptop I’m running it on lose internet access (though not access to the local lan)

I get the following error message (with many different package names) on the command line I’m building from:
Err:33 http://cdn-fastly.deb.debian.org/debian stretch/main amd64 libicu57 amd64 57.1-6+deb9u2
Could not connect to cdn-fastly.deb.debian.org:80 (151.101.120.204). - connect (113: No route to host)

and this in /var/log/syslog shows the container start & the network switchover (that loses internet connection)
May 7 10:57:24 debian avahi-daemon[524]: New relevant interface vethbcff3c1.IPv6 for mDNS.
May 7 10:57:24 debian avahi-daemon[524]: Registering new address record for fe80::989b:4dff:fef4:6b90 on vethbcff3c1.*.
May 7 10:57:38 debian connmand[530]: vethbcff3c1 {newlink} index 6 address 9A:9B:4D:F4:6B:90 mtu 1500
May 7 10:57:38 debian connmand[530]: vethbcff3c1 {newlink} index 6 operstate 6
May 7 10:58:02 debian avahi-daemon[524]: Joining mDNS multicast group on interface vethbcff3c1.IPv4 with address 169.254.165.103.
May 7 10:58:02 debian avahi-daemon[524]: New relevant interface vethbcff3c1.IPv4 for mDNS.
May 7 10:58:02 debian avahi-daemon[524]: Registering new address record for 169.254.165.103 on vethbcff3c1.IPv4.
May 7 10:58:02 debian connmand[530]: vethbcff3c1 {add} address 169.254.165.103/16 label vethbcff3c1 family 2
May 7 10:58:02 debian connmand[530]: vethbcff3c1 {add} route 169.254.0.0 gw 0.0.0.0 scope 253
May 7 10:58:02 debian connmand[530]: vethbcff3c1 {add} route 0.0.0.0 gw 0.0.0.0 scope 253

Does anyone know how to solve this? I’ve already checked that its not related to the laptop disconnecting from wifi.

Solved this, found I had “connmand” installed on the system that was running docker 7 this was interfering. Removed “connman” & docker is able to build successfully.