Random calls are silent on Ooma

[Mr Technician]

Please move if necessary mods. When I switched to Comcast a couple years ago I no longer had a dedicated landline and eventually I settled for Ooma. It generally works well, but regularly it will ring and the person on the other end is silent but they can hear the person using the Ooma. Google wasn't helpful (All I found dealt with all calls being silent). This usually happens when my dad calls from work but it has also happened during calls from someone on a cell phone, so it's not just happening from one caller. I should also mention that it only happens on inbound calls and the issue is immediately solved by calling the person back. Any thoughts on how to fix this issue? I tend to doubt it's a network issue considering other calls work with no issue. In some ways I want to leave VOIP landline solutions behind entirely and use only cell phones.