Intune application keys have a validity period. Intune supports a validity period of up to 24 months as of December 29, 2021.
If you have to change Intune application values when using the SCEP enrollment method, see this Microsoft document for more information:
Once this validity period has lapsed, you will no longer be able to issue certificates via Intune.
To renew your Intune secret key for your application, follow these steps:
For more information on this please see the following Microsoft document:
When updating in the MPKI 8 portal, note that you need to update ALL of the values even if you are only changing the key.
When All elements are updated, you will see the change. If you only update one value, it will save successfully, however, if you navigate away and come back, you will notice that the original key is still there. You MUST change all three values even though the other two didn’t change.
Once everything is saved, do a test enrollment to validate that the changes are successful. If you continue to receive errors, please contact PKI Support.