Diagnosing an OFFLINE machine

IT Finally opened up the ports but we still show status OFFLINE. Are there any clever ideas on how to test that outgoing or incoming UDP ports are really open, I genuinely do not trust IT. My normal trick of using TCP won’t work since it is UDP

dev@connectria /d/h/dev> sudo systemctl restart zerotier-one.service
dev@connectria /d/h/dev> sudo zerotier-cli status
200 info 185eabf82d 1.6.5 OFFLINE