Our last hope to fix can’t record voicemail on iPhone Verizon, AT&T, Sprint and T-Mobile is to reset network settings. Doing it won’t delete or alter the data, only the VPNs, APNs, Wi-Fi Passwords, Paired Bluetooth Devices, and other network-related settings will reset to default. Navigate to the Settings app. Go to General. Tap Reset and then select Reset Network Settings. Enter the password to proceed and confirm Reset.
This tutorial is going to show you how to record a voicemail greeting that you choose. It is a good idea to either write out or think about exactly what you are going to say before you record the message. You will then have the opportunity to play the greeting back before you set it for any incoming calls that go to voicemail.

Verizon only: Unfortunately, if you have set up the voicemail successfully but still unable to change the greetings of Voicemail from the Voicemail tab, then dial *86 and select option 4 to make a change. Step #1: Launch the “Phone” app on your iPhone. Step #2: Tap “Voicemail”. Step #3: Select “Greeting” on the upper-left corner of the screen. Step #4: In case, you are also using eSIM then select the second network to change voicemail greetings. Step #5: Select “Custom”. From here you can record a greeting. Step #6: Tap “Record”.
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