Hello John, thank you for your reply. I do not believe phonebook size will be an issue for us. No one has more than few hundred contacts. I suspect our issue is to do with our firmware folder(s) being messed up. Unfortunately, we cannot really investigate that ourselves with the hosted version of 3CX. Then, as a partner, it does not seem I can open a support case for our NFR instance. I should mention we had a previous issue a while back where we had used the firmware clean up feature not realizing what would happen, and then the system would not pull down the most current firmware at that time. I incorrectly assumed it would only delete older firmwares, and not the current one at the time. We had to manually update our phones then. Later on, it started to work again once a newer firmware came out.