Hello @TrishaMarie
Thanks for reaching out to our Nest Community about this situation with your Display. I apologize for all the inconvenience. I'm here to help you with that.
I completely understand this situation. Let me lend you a hand to find the solution. Could you help me with some questions?
What are the troubleshooting steps you've already tried?
When did the behavior start?
Was the device dropped or knocked over?
Is the display's Assistant working?
In the meantime, you can try to perform a Factory reset on your Display and check if the black line is still there.
Feel free to reply to me with this information, and I will definitely do my best to find a solution for you.
Best regards,
Douglas.
