Hi all, sorry for bringing up this old message, but I run into the same problem with C9300X model. I couldn't add/create vlan 1200 and following the documentation (Catalyst_9300-M_Series_Installation_Guide) didn't help, I always get stuck on the message > This switch is limited to 1000 vlans, Please check your vlan related configurations on all ports, and static and management vlans on the switch and network. Note vlan 1 is always open. The switch is currently allowing vlans 1,1-300,1100-1600,1-1000.    I tried multiple combinations, resets, but nothing changed, so I found the solution on the reddit , you first need to add vlans 1-300, apply it, and after that to add new set, 1100-1600 and apply it again.   If anyone else runs into the same problem, you can try with this. ... View more