TailScale on Freebsd (XigmaNAS)

Tailscale version 1.6.0
Your operating system & version XigmaNAS - Ornithopter (revision 8419)
12.2-RELEASE-p6 FreeBSD 12.2-RELEASE-p6

XigmaNAS comes as a pre-set custom pack of freebsd packages, It can be installed as embedded, where it would boot from an image every time. With full install one can add packages to it, that is what I have and TailScale 1.6.0 is the available FreeBSD port.

It does work, but only for some time, and then it just stops. I have to reboot the FreeBSD box and then it will work again.

Any ideas how to troubleshoot this?