claimSignature.mismatch
The active claim signature does not verify.
Failure code
What to do
Treat the manifest as untrustworthy. The signed bytes were altered or re-signed after signing; obtain a fresh signed copy from the source.
Verify it yourself
Install the open-source Encypher C2PA CLI and check any file. It runs locally and reports these status codes.
cargo install encypher-c2pa-cli
Build verification into your product
The Encypher API returns these status codes over HTTP. Read the reference to wire provenance checks into your own workflow.