"Error 1934" when accessing voicemail on my iPhone 16 Pro running iOS 18.6

I have a Mac 16 Pro running 18.6. A caller told me that my voice mail. box was full. I didn't have any current messages, and there was an option to see deleted messages. I hit that option, and the page was frozen with a pin wheel churning. Eventually I received an error message. 1934

[Re-Titled by Moderator]

Original Title: Voice mail Greeting error 1934