Not really sure why G-Voice number cannot be used for SMS Verification

[wordsunwords]

Whenever I enter my number (the one that I mainly use for online work; it's my Google Voice number), I get a red box in the lower left corner which says "Invalid account" and to check to make sure that I use +1.  The +1 is already there when I type in my number.  Are G-Voice numbers barred from Zazzle's SMS Verification system?

-Words & Unwords

[Mark]

Hey @wordsunwords,

We do not allow Google Voice and other VoIP numbers to ensure safety in our Community.

Thanks!