Has anyone experiencing this issue made any changes recently with their Verizon account that has Integrated Messaging? Like, change password, add/delete devices or anything? It could be there is something going on with the processes or databases involved on the servers doing the synchronization of messages on devices associated with the accounts. Generally, when this gets escalated to other levels of tech support behind the scenes, we don't hear about what was found and/or fixed. Sometimes things just start working again.