The GS516TP, GS728TP, GS728TPP, and GS752TP smart switches differ in hardware from other smart switches.
On these models, routing mode rather than switching mode is enabled by default. When you change from routing mode to switching mode, or the other way around, from switching mode to routing mode, the switch reboots.
Dynamic VLAN assignment functions only in switching mode. When you disable switching mode and enable routing mode, dynamic VLAN assignment is no longer supported.
For information about enabling dynamic VLAN assignment on smart switch models GS516TP, GS728TP, GS728TPP, and GS752TP, see the “How do I enable dynamic VLAN assignment on smart switch models GS516TP, GS728TP, GS728TPP, and GS752TP