How do you troubleshoot a failed certificate enrollment in TPP?

A failed enrollment in TPP almost always traces back to one of a small number of causes, so working through them in order usually finds the culprit faster than guessing.

1. Check the policy folder's CA connection first — an expired CA credential, a revoked API key, or a network path to the CA that got blocked (a firewall rule, an expired outbound proxy cert) is the single most common cause.
2. Review the request against policy constraints — a CSR asking for a key size, SAN entry, or validity period that the folder's policy doesn't allow will be rejected outright, and TPP's log will usually name the specific constraint that failed.
3. Confirm the requester has permission in that folder; a valid, well-formed request from an account without enrollment rights fails at the authorization step before it ever reaches the CA.
4. Look at the CA's own response code in the TPP activity log — CAs sometimes reject requests for reasons outside TPP's control, like a domain failing CAA record validation or rate limiting on a free CA like Let's Encrypt.

TPP's Log and Workflow views on the certificate object usually show exactly which of these steps failed and why, which is faster than re-submitting the request repeatedly and hoping.