Meteor Accounts Phone, phoneVerificationMasterCode not working

Hello,

We are currently using users phone number and an SMS with verification code as the method of login within our app.

For a number of phone numbers we have setup a ‘phoneVerificationMasterCode’, so that those users are always able to login, even if they have not received an SMS. We do this by providing the following in the settings.json

"accounts-phone": {
  "verificationWaitTime": 0,
  "verificationRetriesWaitTime": 0,
  "adminPhoneNumbers": [“+##########”, "+##########","+##########","+##########","+##########"],
  "phoneVerificationMasterCode": "1111”
},

As SMS service we are using Plivo. However it seems that the above configuration is not working. With any of the numbers that are registered there, they are not able to user the verification code as provided in the settings.

Has anyone experience this? Or is aware of what might be the issue?
Thanks in advance.