what is my mistake
* Slot-1 Stack.3 # configure stpd "s0" add "vlan100" ports 1:1-6
Error: Cannot assign vlan vlan100 port 1:1 to STP domain
Error: Cannot assign vlan vlan100 port 1:2 to STP domain
Error: Cannot assign vlan vlan100 port 1:3 to STP domain
Error: Cannot assign vlan vlan100 port 1:4 to STP domain
Error: Cannot assign vlan vlan100 port 1:5 to STP domain