Hello Ese Iboyi,
Thank you for posting on the Microsoft Community Forum. I hope you're doing well.
I understand that you're experiencing this issue with the Outlook Android app. Based on the information you've provided, it seems that the error occurred during the authentication process, which could be caused by a number of factors such as incorrect login credentials, server issues, or outdated device or app version.
To better understand and narrow down the matter, please provide more information so that we can work together to address it effectively.
1. Can you post a screenshot of the error?
2. Can you share what app version you have?
3. May I know What android phone model you have?
4. Are you able to sign in to your Outlook desktop application or Outlook on the Web?
Looking forward to your response. I will continue to assist you based on the information you provide. Your understanding and cooperation are highly appreciated.
