# Firefox Error: getOperatorList - ignoring errors during "GetOperatorList: page 0" task: "DataCloneError: The object could not be cloned." **URL:** \ **Category:** Technical Support\ **Tags:** pdfjs-express\ **Created:** [July 23, 2021, 12:05pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897 "2021-07-23T12:05:24Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![shahkartikk](https://avatars.discourse-cdn.com/v4/letter/s/5fc32e/32.png) [@shahkartikk](https://pdfjs.community/u/shahkartikk)\ **Post date:** [July 23, 2021, 12:05pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/1 "2021-07-23T12:05:24Z")
Hi Team, I am facing below issue in the pdf.worker.js file, while viewing the document on the PDF.js Express Viewer. The issue is only occurring in the FireFox Browser(of course my browser is up to date), other working perfectly fine in Chrome and Edge. **getOperatorList - ignoring errors during “GetOperatorList: page 0” task: "DataCloneError: The object could not be cloned."** Please advice if I need to upgrade version of PDF.js Express, currently I am using 7.3.3. Warm Regards Kartik ---
**Author:** ![shahkartikk](https://avatars.discourse-cdn.com/v4/letter/s/5fc32e/32.png) [@shahkartikk](https://pdfjs.community/u/shahkartikk)\ **Post date:** [July 23, 2021, 5:17pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/2 "2021-07-23T17:17:21Z")
Can anyone please revert on my query ? Warm Regards, Kartik ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [July 27, 2021, 2:26pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/3 "2021-07-27T14:26:31Z")
Hi there, Unfortunately I cannot reproduce your issue. - Does it happen with all documents or just a certain one? - Are you able to link me to a url/repo where you can reproduce? - Do you have any code that may be causing this issue? Please share a code snippet of how you are using Express PS. Next time, please fill out the issue template correctly as it prevents me from having to ask follow up questions. Thank you! Logan ---
**Author:** ![shahkartikk](https://avatars.discourse-cdn.com/v4/letter/s/5fc32e/32.png) [@shahkartikk](https://pdfjs.community/u/shahkartikk)\ **Post date:** [July 27, 2021, 2:49pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/4 "2021-07-27T14:49:06Z")
Hi Logan, I will come back to you with the details you asked. However, which issue template you are saying me to fill out? I am already wondering that I didn’t get any revert from your side since Friday, 23Jul. Warm Regards ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [July 27, 2021, 3:19pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/5 "2021-07-27T15:19:18Z")
Hi there, When you create a new issue there is a template that it asks you to fill out. 2 business days for a support response is very typical, _especially_ for a free support channel. Please keep in mind that the people providing support also develop the software, so we need to manage our time accordingly. Looking forward to further details, Thanks, Logan ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [July 29, 2021, 8:10pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/7 "2021-07-29T20:10:40Z")
Moving this conversation [here](https://pdfjs.community/t/after-updating-chrome-firefox-browser-to-latest-version-pdf-viewer-js-doesnt-show-barcodes-qrcodes/905/4). ---
**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\ **Post date:** [July 29, 2021, 8:10pm UTC](https://pdfjs.community/t/firefox-error-getoperatorlist-ignoring-errors-during-getoperatorlist-page-0-task-datacloneerror-the-object-could-not-be-cloned/897/8 "2021-07-29T20:10:43Z")