Within Teamwork Projects, the notifications system could be blocked by your internal network or firewall.
The port that this is available through is 8840.
If you are experiencing issues receiving notifications, ask your system administrator to ensure that this port is open (outbound).
For our US region, the host is tw-socket.teamwork.com. IP addresses for this host will change over time.
For our EU region, the host is tw-socket.eu.teamwork.com, IP addresses for this host will change over time also.
For more information, see: Email notification issues