Merge pull request #2560 from jku/tweak-sign-failure

metadata API: Tweak exception message on sign failure

Author: jku

tuf/api/metadata.py

@@ -384,7 +384,7 @@ def sign(
         try:
             signature = signer.sign(bytes_data)
         except Exception as e:
-            raise UnsignedMetadataError("Problem signing the metadata") from e
+            raise UnsignedMetadataError(f"Failed to sign: {e}") from e
 
         if not append:
             self.signatures.clear()