I had an identical problem with the same error message but the solution with removal of unused docker networks didn't help me. I've deleted all non-default docker networks (and all images and containers as well) but it didn't help - docker still was not able to create a new network.
The cause of the problem was in network interfaces that were left after OpenVpn installation. (It was installed on the host previously.) I found them by running ifconfig
command:
...
tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:10.8.0.2 P-t-P:10.8.0.2 Mask:255.255.255.0
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:75 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:84304 (84.3 KB) TX bytes:0 (0.0 B)
tun1 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:10.8.0.2 P-t-P:10.8.0.2 Mask:255.255.255.0
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:200496 errors:0 dropped:0 overruns:0 frame:0
TX packets:148828 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:211583838 (211.5 MB) TX bytes:9568906 (9.5 MB)
...
I've found that I can remove them with a couple of commands:
ip link delete tun0
ip link delete tun1
After this the problem has disappeared.