---
title: "PDF digital signature validation issues | Nutrient"
canonical_url: "https://www.nutrient.io/guides/web/signatures/digital-signatures/troubleshooting/chain-of-certs-not-valid/"
md_url: "https://www.nutrient.io/guides/web/signatures/digital-signatures/troubleshooting/chain-of-certs-not-valid.md"
last_updated: "2026-05-15T15:53:41.709Z"
description: "Learn about the different validation statuses of digital signatures and how to resolve common issues."
---

# Understanding digital signature validation statuses

A digital signature can be in three different states:

- **Valid** — This state indicates that the document's integrity is intact, the certificates are valid, and there is a trustworthy certificate path from the signature certificate to a trusted certificate.

- **Invalid** — In this state, the document's integrity has been compromised (e.g., it was modified after signing).

- **Indeterminate** — When Nutrient encounters an indeterminate signature, it displays a yellow Emoji, banner, or similar indicator, along with the text "at least one signature has problems".

Here are the most common reasons for this indeterminate validation state:

- The signing certificate is self-signed. To understand the difference between a self-signed certificate and a certificate issued by a certificate authority (CA), refer to [certificates for signing](https://www.nutrient.io/guides/web/signatures/digital-signatures/signature-lifecycle/prepare-the-certificates-for-signing.md).

- The signing certificate's certificate issuer (CA) is not included in the Nutrient keystore. The keystore allows Nutrient to trust specific certificates.

To learn how to trust certificates, read the [signature validation](https://www.nutrient.io/guides/web/signatures/digital-signatures/signature-lifecycle/validation.md#provide-trusted-root-certificates) part of the signature lifecycle section.
---

> Part of [Troubleshoot common digital signature issues](/guides/web/signatures/digital-signatures/troubleshooting.md)

## Related pages

- [Document Modified Since Signature](/guides/web/signatures/digital-signatures/troubleshooting/document-modified-since-signature.md)
- [Invalid Signatures](/guides/web/signatures/digital-signatures/troubleshooting/invalid-signatures.md)