When the QuickBooks Web Connector can't connect to your WooCommerce store, the cause is almost always something on your site: a security rule, a firewall, a server setting, or a piece of code on your site adding unexpected output. This article walks through the most common causes and how to fix each one.
You may see errors in your Web Connector like:
"Authentication failed"
"Response is not well formed XML"
"The request failed with HTTP status 403: Forbidden"
"The request failed with HTTP status 500: Internal Server Error"
"Receive Response XML Failed"
QBWC1012, QBWC1041, QBWC1042
Before you start
There's no need to remove/re-add our sync to your Web Connector. This doesn't change/solve connection issues. Start with the steps below.
The fastest way for us to help: in the Web Connector, click View Log, save the log file, and send it to support@myworks.software with a description of the issue you're seeing. Don't forget to let us know if anything has recently changed in your WooCommerce store or QuickBooks company.
Start here: what's likely the cause?
If you know the error code
What the Web Connector shows | Likely cause | Go to section |
403 Forbidden | Firewall or security rule blocking the sync | 1, 3, 4 |
500 Internal Server Error | Your host's security firewall, or a site error | 2, 6 |
302 Found | CAPTCHA or bot protection | 4 |
"Response is not well formed XML" | Site is returning broken output | 5 |
"Authentication failed" (no HTTP error) | Host is blocking the Web Connector, or site is returning broken output | 2, 3, 6 |
QBWC1048 / certificate error | SSL/TLS issue — see separate article |
|
If you're not sure about the error code, check your hosting
Hosted with... | Likely cause | Go to section |
Cloudflare (in front of your site) | Cloudflare's firewall is blocking the Web Connector | 1 |
Nexcess, Dreamhost, Liquid Web, InMotion, A2 Hosting | Your host's security firewall | 2 |
Siteground | Your host is blocking the Web Connector's identity | 4 |
WP Engine | WP Engine's bot protection | 4 |
Wordfence, iThemes Security, Solid Security, or similar | Your security plugin is blocking the Web Connector | 5 |
Causes and solutions
1. Cloudflare is blocking the Web Connector
Signs this is the cause
Your site uses Cloudflare
403 Forbidden in the Web Connector log
Why it happens Cloudflare's firewall doesn't recognize the QuickBooks Web Connector and treats it as suspicious traffic.
How to fix it In your Cloudflare dashboard (Firewall > Firewall Rules), add a firewall rule to skip or allow requests where:
The URL contains
mw_qbo_desktop_qwc_server, orThe source IP equals your QuickBooks computer's IP (you can find this by visiting whatsmyip.org on your QuickBooks computer)
2. Your web host's security firewall is blocking the sync
Signs this is the cause
Site hosted on Nexcess, Dreamhost, Liquid Web, InMotion, or A2 Hosting
500 Internal Server Error in the Web Connector log
Sync may start successfully and then fail partway through
Why it happens Managed WordPress hosts run a server-level firewall (often called ModSecurity) that sometimes flags the Web Connector's requests as suspicious.
How to fix it Contact your hosting support and ask them to whitelist the Web Connector's connection. A ready-to-send message is in Messages you can send below.
3. WP Engine's bot protection is blocking the Web Connector
Signs this is the cause
Site hosted on WP Engine
Authentication-failed errors with no obvious HTTP error code
Issue may have started after a new WP Engine install or environment change
Why it happens WP Engine has a feature called "redirect bots" that can intercept the Web Connector and block its requests.
How to fix it Contact WP Engine support and ask them to disable "redirect bots" for your install.
4. A security plugin or CAPTCHA is blocking the sync
Signs this is the cause
Your site uses Wordfence, iThemes Security, Solid Security, or a similar security plugin
Or you recently added a CAPTCHA, Turnstile, or other bot protection to your site
The issue started right after that plugin was enabled or that protection was added
Why it happens These tools see the Web Connector as automated traffic and block it.
How to fix it In your plugin's settings (or in your CAPTCHA service's configuration), add an allow-list rule for requests whose URL contains mw_qbo_desktop_qwc_server. Most security plugins have a URL-based allow-list under their firewall settings.
5. Your site is returning a broken response
Signs this is the cause
Error: "Response is not well formed XML" or "Authentication failed due to the following message"
Your site works normally in a browser, but sync keeps failing
Recent theme, plugin, or custom-code changes on your site
Why it happens Something on your site — usually in a custom theme or plugin — is adding extra blank space or characters to the beginning of your site's response. This breaks the format the Web Connector expects.
How to fix it This is almost always a developer-level fix. Send the developer message below to your developer.
If you don't have a developer, MyWorks Support can often identify the issue directly - reach out to us and we'll help take a look as a courtesy.
6. Staging site requires a password
Signs this is the cause
Setting up the sync on a staging or development site
QBWC1048 error when adding the QWC file
Your browser shows a username and password popup when you visit the site
Why it happens The QuickBooks Web Connector doesn't support HTTP password protection (also called Basic Auth).
How to fix it Either remove the password protection from your staging site, or ask your developer to exclude the URL index.php?mw_qbo_desktop_qwc_server=1 from password protection.
Messages you can send to your host or developer
Message to your host (for Nexcess, Dreamhost, Liquid Web, InMotion, A2)
Hi,
I'm trying to connect the QuickBooks Web Connector on my computer to my WooCommerce store, and I'm getting a 500 Internal Server Error. Based on the response, this looks like it's being blocked at the server level by a security firewall like ModSecurity — the error page appears to be the default server error page, not something from my WordPress install.
Could you please:
Check your ModSecurity (or server firewall) audit log for my site around [time of your last failed sync attempt]
Either whitelist the rule that matched the Web Connector's request, or disable ModSecurity for just the URL
/index.php?mw_qbo_desktop_qwc_server=1on my site
The connection is coming from the IP address [your QuickBooks computer IP — find it at whatsmyip.org], with the user-agent Mozilla/4.0 (compatible; MSIE 6.0; MS Web Services Client Protocol ...).
Thanks!
Message to your web developer (if your site is returning a broken response)
Hi,
Our QuickBooks sync is failing because our site is adding extra blank space or characters to the top of its response, before the XML content starts. This breaks the format that the QuickBooks Web Connector expects.
This is almost always caused by one of two things:
A stray blank line after a PHP closing tag (
?>) in a custom theme or plugin fileA PHP file saved with an invisible BOM (byte-order mark)
Could you:
Review recently-added or recently-edited custom code (theme
functions.php, any custom plugins)Or disable plugins one at a time until the extra whitespace disappears from the site's response
MyWorks support can provide additional context if helpful — reach out to them at support@myworks.software.
When to contact MyWorks support
If none of the categories above match your situation
If you've sent a template message to your host or developer and they're having trouble solving this.
Please include your Web Connector log with any support request. In the Web Connector, click View Log and attach the file when emailing our support.