Grandstream phone VLAN voice an data same port

Hi I have an issue with a Dell N1500 switch and a Grandstream phone. Reading best practices documents. I configured the port like this:

interface Gi1/0/17

switchport mode general

switchport general pvid 500

switchport general allowed vlan add 500

switchport general allowed vlan add 55 tagged

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VLAN 500 is data and VLAN 55 Voices.

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If I have the port with this configuration I can reach the gateway in the PC. But the phone cant register to the central IP. If I remove the switchport general pvid 500. The phone can register to the central IP but I cant reach the PC gateway.

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Any suggestion?