Dear Michael,
I am an independent advisor, and I am trying to help other users in Community with my experience in Microsoft products.
I assume you are using Outlook app on your Kindle. This sometimes happens with the mobile application. In order to resolve this please try to do the following:
1. Check for System updates for your phone
2. Remove the account from Outlook app
3. Delete Outlook app
4. Go to store and check for updates
5. Download and install Outlook app and set up your account using this support article
https://support.office.com/en-us/article/set-up...
Please share the results.