The unlocked model might not be compatible with VoLTE on Verizon Wireless.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
LAMMCN53, ensuring that your phone is working at its best for you is important to use. We are here to help out with your VoLTE inquiry. Bearone21 and Ann154 are both on the money with this. Advanced Calling must be on, however, there is a good chance that your model of the Note 8 may not be able to utilize this feature. Check and see if this setting roadmap leads you to the option for VoLTE Calls:
Settings> Connections > Mobile Networks > VoLTE Calls.
That setting must be set to ON, if available, for this feature to work for you. Please keep us posted.
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I have the same phone and same problem. I fixed it by going to settings->connections->mobile networks->network mode. It was set to global. I set it to LTE/CDMA. That solved my problem. I live in Illinois. I did not need the global option. When I travel outside the US I can switch it back. Hope this helps.