Seeing an error with a mysterious number attached can always raise a concern, turtlesong. You are in a great place to get some expert advice. The error “9001” means that the voicemail is having trouble connecting to the server. This error can be resolved by “clearing the app cache” for your voicemail app. Here are the steps: https://www.verizonwireless.com/support/knowledge-base-214978/. Once you complete this step, be sure to power the device down fully for at least two minutes. Power it back on, and test out the voicemail. Please keep us posted on what happens.