T22/T28 not connecting to voice vlan

[imabev]

I have many of these phones connected to a 3CX phone system. All are currently working. At one remote location I have replaced a switch (from HP to Dell). The phone are working at this location. However, they will not boot correctly to the voice vlan without intervention.

Here's what happens: Theres two vlans - voice and data. If we take it from the beginning on a factory reset, the phone boots and gets a DHCP IP address on the data vlan. The phone picks up dhcp option 66 and goes to the provisioning server and pulls down the confg. The phone then saves the config but still remains on the data vlan. On all of my other HP switch this happens normally (it switches to the voice vlan).

The only way I can get this to work is: AFTER the phone boots with the provisioning template, I have to shut off the port, remove the data vlan from port (leaving only the voice vlan), allow the phone to boot and then it registers. I can then manually add back in the data vlan to the port and the PC has connectivity.

Theres a piece missing that ultimately switches this phone back to the the voice vlan and I cannot figure it out. I have tried many different options including several combinations of voice vlan config on the switch, lldp, lldp-med, etc...What else can I try?