Hello Rebecca Dickson
Thank you for reaching out to the Microsoft community!
Based on the information you have shared with us I understand you are having an issue with Microsoft authenticator not showing a notification to enter the sign verification code.
As this issue in more related to the Microsoft authenticator application I would recommend posting this concerns in our deducted community for Microsoft Authenticator - Microsoft Q&A. You will be able to find experts specialized in the "Microsoft Authenticator" that can provide customized solutions this unique situation.
You can also check the MS Authenticator FAQs Microsoft Microsoft Authenticator FAQs - Microsoft Support
I apologize for redirecting you to a different community but I believe this will ensure faster and more accurate assistance for your specific scenario.
I appreciate your patience and understanding. Have a great day!