I am also having a bit of trouble; for reference, unraid is behind pfsense, which I've been using for a while. The new update doesn't allow deluge to connect. On current build with nextgen files added. IPv6 enabled or disabled, still the same issue and won't get past this part:
kernel: docker0: port 4(veth5cfa152) entered disabled state
kernel: device veth5cfa152 left promiscuous mode
kernel: docker0: port 4(veth5cfa152) entered disabled state
avahi-daemon[7207]: Withdrawing address record for fe80::5c93:22ff:fef5:3030 on veth5cfa152.
kernel: docker0: port 4(vethebe7b8a) entered blocking state
kernel: docker0: port 4(vethebe7b8a) entered disabled state
kernel: device vethebe7b8a entered promiscuous mode
kernel: docker0: port 4(vethebe7b8a) entered blocking state
kernel: docker0: port 4(vethebe7b8a) entered forwarding state
kernel: eth0: renamed from vethe5d019a
kernel: IPv6: ADDRCONF(NETDEV_CHANGE): vethebe7b8a: link becomes ready
avahi-daemon[7207]: Joining mDNS multicast group on interface vethebe7b8a.IPv6 with address fe80::5c84:3aff:fe61:9d57.
avahi-daemon[7207]: New relevant interface vethebe7b8a.IPv6 for mDNS.
avahi-daemon[7207]: Registering new address record for fe80::5c84:3aff:fe61:9d57 on vethebe7b8a.*. <--------won't get past this part
EDIT: if you are running into a similar problem, I found switching servers was the answer. Originally, I was trying to connect to DE Frankfurt, as it was part of the BETA, but wouldn't connect. UK Manchester does work though. More testing will need to be done to find an acceptable server.