I've added a SIP account on my Pixel using these steps:
Phone/Settings/Calls/Calling Accounts/SIP Accounts/+ (to add new SIP Account settings)
The account is registered and ready but once I set the phone to use SIP:
Phone/Settings/Calls/Calling Accounts/Make Calls With/ *SIP Account* (choose the SIP account just added)
and
Phone/Settings/Calls/Calling Accounts/Use SIP Calling/For all calls
I get this message:

My initial research indicates that call barring is a carrier-level setting. The options are as follows:
Barring of all outgoing calls
**33*password# - Activate
#33*password# - Deactivate
*#33# - Check the condition
Barring of all calls
**330*password# - Activate
#330*password# - Deactivate
*#330# - Check the condition
Barring of all outgoing international calls
**331*password# - Activate
#331*password# - Deactivate
*#331# - Check the condition
Barring of all outgoing calls
**333*password# - Activate
#333*password# - Deactivate
*#333# - Check the condition
Barring of all incoming calls
**353*password# - Activate
#353*password# - Deactivate
*#353# - Check the condition
Barring all incoming calls when roaming
**351*password# - Activate
#351*password# - Deactivate
*#351# - Check the condition
Call Barring
Change the password for all bans (default - 0000)
- ** 03 * 330 * old password * new password * new password #
Using any of the codes to check the condition (example: *#33#) fails. Changing condition requires a 4 digit password, suggested as 0000. I've also tried the last 4 digits of my Verizon number and neither works.
I've spoken to my local Verizon store and neither the sales person nor any of the more advanced, technically savvy staff members can help.
My research found the same issue with other carriers and it they were able to change it on the carrier end.
What do you suggest?