Layer 3 LAN ports, WAN interfaces and subinterfaces, and some software features use internal VLANs in the extended range. You cannot use an extended range VLAN that has been allocated for internal use.

The same VLAN cannot be recreated if it is used internally by the switch. Issue the show vlan internal usage command in order to check the internal status of a VLAN.

In order to resolve this issue, configure the internal VLAN allocation policy either in ascending or descending order, as shown:

Router(config)#vlan internal allocation policy ? 
              ascending Allocate internal VLAN in ascending order 
              descending Allocate internal VLAN in descending order 

During the configuration of the internal VLAN allocation policy, select one of these procedures:

• Enter the ascending keyword in order to allocate internal VLANs from 1006 and higher.  

• Enter the descending keyword in order to allocate internal VLAN from 4094 and lower.

Note: The internal VLAN allocation policy is applied only after a reload.

Alternatively, if you cannot reload the switch to make the vlan allocation change, you can translate the higher dot1q vlan-id to a lower dot1q vlan-id not being used by internal processes.

Refer to the Configuring the Internal VLAN Allocation Policy section of Configuring VLANs for more information.