The Problem was IPTables all along, when I reboot the rules get cleaned, and I need to add the first two. sudo iptables -L -n -v | grep 5060 4 208 ACCEPT 6 -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:5060 13 13715 ACCEPT 17 -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:5060 0 0 ACCEPT 6 -- !br-aeab3c66b5ee br-aeab3c66b5ee 0.0.0.0/0 172.19.0.6 tcp dpt:5060 0 0 ACCEPT 17 -- !br-aeab3c66b5ee br-aeab3c66b5ee 0.0.0.0/0 172.19.0.6 udp dpt:5060