Error in sandbox retrieving signed pdfs with Java SDK

We just started receiving this error in the sandbox environment when attempting to download signed pdfs.  I don't believe anything has changed on our side for quite a while now. I removed the email address from the error message below, but it was the account owner's email address and not the email of the sender id.  The account owner in this case is not a signer on the transaction so I'm confused by the error message 'signer cannot be found'.

We are using Java SDK 11.45.

com.silanis.esl.sdk.internal.EslServerException: Failed to retrieve pdf for package XEOv_fgHx-vFGVvVOJE8OermvOo=. Exception: HTTP GET on URI https://sandbox.esignlive.com/api/packages/XEOv_fgHx-vFGVvVOJE8OermvOo=/documents/1663165878382/pdf?flatten=true resulted in response with status code: [404, Not Found]. Optional details: {"messageKey":"error.notFound.signerNotFound","technical":"user: {account owner email address} not available for process: XEOv_fgHx-vFGVvVOJE8OermvOo=","code":404,"message":"The specified signer cannot be found.","name":"Resource Not Found"}