The mail app is in-built into all of your Mac and iOS devices. It is a powerful tool that allows you to manage and add all your email accounts on one platform. Here are some of the reasons your Apple mail might fail to work or stop responding on your Mac and iOS devices. Before you begin with the technical fixes, we recommend restarting your device. In many instances, rebooting helps with minor issues occurring in the app as it refreshes and removes all your temporarily stored data. If this doesn't working just call Mac Mail has a toll-free customer service number +1-833-836-0944 and a website to provide phone support on a 24/7 basis.