1034 error code on iPhone 13

When I click on Greeting to set up my voice mail on my phone, I receive a pop up box error that says: The operation couldn’t be completed.(com.apple.mobilephone error 1034). Then the box disappears and the screen just sits there cycling saying “retrieving greeting” at the top. My voicemail has been set up, but now it tells me it isn’t. I can’t change the setting from default to custom.