Issue with Generating Digital Signature Using Private Key

Hello,

I am currently facing an issue while attempting to generate a digital signature using a private key that is attached to a certificate. I have been using the following code snippet successfully for some time:

var signer = cert.createSigner({

 certId: certId,

 algorithm: cert.HashAlg.SHA256,

});

signer.update(hashedInvoice);

var digitalSignature = signer.sign();

However, suddenly the process stopped working and I am encountering the following error message:

{

  "type": "error.SuiteScriptError",

  "name": "SIGNING_ERROR",

  "message": "An error has occurred during digital signature generation.",

  "id": "",

  "stack": [

   "createError(N/error)",

   "signDocument(/SuiteScripts/_az_einv_sa_testsignature.js:57)",

   "afterSubmit(/SuiteScripts/_az_einv_sa_testsignature.js:9)"