1:
2:
2b : Check if Self sign Certificate is uptodate if using Https .
or else regenerate : https://draytek.co.uk/support/guides/kb-regenerate-certificate
3:
4: Check System Parameters – 59 and 60
5: Check Stun Settings
6: Check port 8069
7: Check Firewalls and open ports
8: Video on how to set TR069