<< New discussion started due to age of previous thread >>
I know this is an old question, but it still prevails. I searched for a solution recently and, after trying "all of the above", found what seems to have caused the problem: multiple listings for the same contact. Deleting all the contact entries fixed the problem.
Here's the story: My husband's Droid stopped receiving calls from my Samsung Galaxy. I teased him that he was ignoring my calls because I usually heard several rings before it went to voicemail. He insisted his phone never rang, but he got the "Droid" voicemail notification. Yesterday, we tested it sitting right next to each other. I dialed his number, but his phone never rang, even though I heard several rings through my phone before it went to vm. I checked his contact list, and his phone had 7 entries for me, all slightly different. (Maybe there was a data conflict in the combination of multiple Google contact entries, backup entries, manual entries, etc. that prevented the call from going through?) I deleted all the entries for myself on his phone, called his phone from mine, and my call went through normally. I saved my call as a new contact on his phone, and now he hears his phone ring when I call.