Error response from daemon: Pool overlaps with other one on this address space (when on VPN)

In Ubuntu I am trying to create a docker network with a specified subnet when on VPN but I get the below error:

$ docker network create my-network --subnet 172.17.24.0/18
Error response from daemon: Pool overlaps with other one on this address space

Looking at the route table:

$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         0.0.0.0         0.0.0.0         U     0      0        0 cscotun0
0.0.0.0         192.168.0.1     0.0.0.0         UG    20600  0        0 wlp0s20f3
10.174.33.0     0.0.0.0         255.255.255.0   U     0      0        0 cscotun0
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 cscotun0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 wlp0s20f3
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
188.64.152.45   192.168.0.1     255.255.255.255 UGH   0      0        0 wlp0s20f3
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 cscotun0
192.168.0.0     0.0.0.0         255.255.255.0   U     600    0        0 wlp0s20f3
192.168.0.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlp0s20f3

I don't see that my VPN (cscotun0) is occupying that range so what is going on?

Unless 172.17.24.0/18 is overlapping with docker0:

172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0

but I assume both docker0 and 172.17.24.0/18 should be able to exist in the same range?