# Troubleshoot digital signatures on Android devices

Troubleshoot common issues you might encounter when setting up signatures.

- [I have a chain of certificates that I used for signing but when I validate the digital signature in Nutrient it shows as “not trusted”](https://www.nutrient.io/guides/android/signatures/troubleshooting/chain-of-certs-not-valid.md)

- [I am signing a document with multiple digital signatures and previous signatures show as “not valid”](https://www.nutrient.io/guides/android/signatures/troubleshooting/multi-signatures-previous-not-valid.md)
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## Related pages

- [Robust digital signature support on Android](/guides/android/signatures/digital-signatures/supported-methods.md)
- [Understanding digital signatures in Android apps](/guides/android/signatures/digital-signatures/overview.md)
- [Understanding PAdES and CAdES digital signatures](/guides/android/signatures/digital-signatures/standards.md)