Hmm, strange. What happens when they call? Is it going to voicemail or giving them any kind of error message? You may them try dialing the number manually to see if that works. If the issue continues, you'll want to Contact Us so we can have our Tech Care folks file a Trouble Ticket for you.
The caller would hear a ring on their end, but there was no notice of a call on my end. I would just get a missed call notification. I uninstalled and reinstalled the app and that seemed to fix it.
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