I have a Cisco SG300-10PP switch. It has become convinced that the voice VLAN should be 64 and I cannot disabuse it of that notion. I have reset it to factory defaults and it still thinks this. I have manually set the voice VLAN ID to 68, which is what I want it to be. The upstream switch is telling it 68 via CDP, but the SG300 still thinks that the agreed upon VLAN is 64. I deleted the VLAN off the switch, but as soon as I connect a phone, it recreates the VLAN. I am not sure how to fix this issue. The switch is running version 188.8.131.52. I tried setting the port to trunk mode as one of the posts suggested but that did not seem to help. When I edit the Smartport Type settings for ip_phone or ip_phone_desktop, the voice VLAN number is not changeable.
I would appreciate any help on how to get this working the way that it should.