Replica set node not rejoining set after system reboot

Hi. I have a 3 node MongoDB replica set that is working great. However, after a system reboot (Ubuntu) of one of the nodes, the mongd instance starts up no problem, and systemctl status shows that it is “active (running)” however an rs.status() shows that the node is unreachable and has not rejoined the replica set. We’ve tried adding --replSet to the systemd service as well as:

After=systemd-networkd-wait-online.service
Wants=systemd-networkd-wait-online.service

to no avail. Has anyone else experienced this problem and know of a workaround or solution? Thanks very much.