I had a similar issue with Tang on Ubuntu 20.04.2 that caused tangd.socket not not auto start after most reboots. Simualr to the RHEL bug linked in th previous comment, I was able to fix it by replacing "WantedBy=multi-user.target" with "WantedBy=sockets.target" in /lib/systemd/system/tangd.socket.
I had a similar issue with Tang on Ubuntu 20.04.2 that caused tangd.socket not not auto start after most reboots. Simualr to the RHEL bug linked in th previous comment, I was able to fix it by replacing "WantedBy= multi-user. target" with "WantedBy= sockets. target" in /lib/systemd/ system/ tangd.socket.