Hello.
As you can see, your DID 1204272XXXX is receiving incoming calls correctly. One of us tried to verify the phone number 1204272XXXX in a VoipDiscount account and effectively the following error appeared (we chose verification through Call; it's the same error you told us):
"
An error occured while trying to verify your phone number. Please try again using a different phone number or when this verification is following a payment try using a different non-creditcard payment method (Error 108).
"
Let's see the following statements:
1) The DID 1204272XXXX is receiving incoming calls correctly.
2) The verification chosen was just to make a call to 1204272XXXX to listen the 4 digits code for then to type them in the respective inputbox. This is just an incoming call to 1204272XXXX.
From 1) and 2), it seems like since the DID 1204272XXXX is receiving incoming calls correctly, it's the VoipDiscount end which is not sending the call for verification. In this way, the issue is originated directly in the VoipDiscount (or their providers; and probably the same is applicable to other clones of) which are not being able to make a call to the DID 1204272XXXX. This may be caused due to the VoipDiscount end has the DID number 1204272XXXX banned for verification purposes. Finally, it's clear that since the blocking (e.g. not able to call to 1204272XXXX) is happening at the VoipDiscount part, the solution has to be done by them and not us.
We would suggest you to contact them again to try making maybe a manual verification (that they personally call you through 1204272XXXX).