USG 1100 - DHCP issue - stops serving IP addresses

RobT

 lan1, lan2 and 2 VLANs are all Class C /24.  lan1 has infinite lease, lan2 has 2-day lease, VLAN1has 14-day lease and VLAN 2 has 1 day lease (guest network). DHCP reservation is used in place of static IP addresses.

Zyxel_Kevin

Hi @RobT,
Is there any error log ?  Please kindly take the screenshot for me . 
Thank you.
Kevin