## The problem
Issue adobe/pdfservices-node-sdk-samples#42 (closed, 3 comments): The reporter followed the export-pdf-to-jpeg sample with a copied credentials.json and private key. Conversions that used to work suddenly started failing with "Exception encountered while executing operation ServiceApiError" (HTTP 400, errorCode UNKNOWN). Another user replied they were hitting the same failure on PDF extraction, and it went away after upgrading the SDK to 3.3.0. The Adobe maintainer then confirmed the issue was resolved and closed the thread.
## What to do
If Export PDF to Images suddenly starts failing with a bare ServiceApiError (HTTP 400, errorCode UNKNOWN) and your code and credentials have not changed, this was a broken SDK release, not your code. Upgrade @adobe/pdfservices-node-sdk to 3.3.0 and retry. A second user hit the same failure on PDF extraction and confirmed the upgrade fixed it, and the Adobe team closed the thread as resolved. If it still fails after the upgrade, double check your credentials.json and private key are valid, then re-run with logging on and look at the requestTrackingId in the error output when asking for help.