@Alistair Hutson , Thanks for posting in Q&A. From your description, I know your outlook mobile app request to change PIN to 8 digits, but your policy is set to 6 digits. If there is any misunderstanding, feel free to let us know.
Based on my research, I find there’s a known issue with outlook which causes our issue. A new released version 4.2240.4 of the Outlook App in the Play Store seems can resolve the issue.
You can change back to a 6-digit PIN in compliance policy and try the following steps to see if the issue is fixed.
If you are still seeing the message (and haven’t reset your PIN) then you can do the following:
• Open Google Play Store
• Search for Microsoft Outlook
• Install the available Update
• Once the update completes, restart your phone and Microsoft Outlook should then behave as normal
If you had already reset your PIN and want to put it back to 6 Digit’s, then follow the above steps and once your phone has restarted you can go into Device Settings > Lock Screen > Lock Screen Type and change your PIN back to 6 Digits.
Hope the above information can help you.
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