Error connecting to QuickBooks: Authentication Failed / Could not verify the web application server certificate

Learn how to resolve this Authentication Failed error when adding your QWC file to the web connector.

Written by the MyWorks Team

Updated at February 23rd, 2024

Table of Contents

Are you getting the below error message when attempting to add MyWorks Sync / your QWC file to the Web Connector?


Error Connecting to QuickBooks: Authentication Failed

QBWC 1048: QuickBooks Web Connector could not verify the web application server certificate. QBWC 1051: The new application was not added


This usually means that QuickBooks is unable to verify a valid SSL on your website.  However, there are several additional causes/resolutions for this:

  • Ensure a fully valid SSL certificate is correctly installed on your site. Self Signed certificates are not valid.
  • Ensure your local and remote firewall/security plugins are not blocking the QuickBooks connection to your site. Your site does need to be publicly accessible to be connected with. If you have a security plugin on your site, temporarily disabling it while adding the QWC file above usually resolves this issue.
    • An example of a security plugin that can cause this is iThemes Security.
  • If none of the above issues seem to be the cause, there may be an issue with your QuickBooks computer not using a TLS version that your website supports. If this is the case, your site may not load in Internet Explorer on your QuickBooks Computer.
    • To resolve this, you may download and run the TLS readiness tool by QuickBooks using this link or the attachment below. This is within the QuickBooks Tool Hub, which can be downloaded with the above link. Follow the instructions in the above doc from QuickBooks to run it: Close QuickBooks and the web connector, then download and run this tool. After restarting your computer, you should be able to connect our sync without seeing the error above!