Gluetun DSM7.2 connection issues

[gizbug]

After installing Glueton on my Synology NAS I keep getting this error:

ERROR HTTP response status is not OK: 500 500 Internal Server Error: dialing: dial tcp4: lookup cloud flare.com on 1.1.1.1:53: write udp 172.20.0.3:50239->1.1.1.1:53: write: operation not permitted INFO Shutdown.

Any ideas? Haven't run into the issue before, but I'm not sure what changed (maybe 7.2DSM on synology)? Firewall on NAS is off, and i use a Unifi UDRPro router