Short Answer 
To solve the “nocaptcha user response code is missing or invalid” error, first reload the page, then check your internet connection for stability. If issues persist, clear your browser’s cache and cookies to eliminate any data-related problems with CAPTCHA responses.
Step 1: Reload the Page
If you encounter the error message stating that your nocaptcha user response code is missing or invalid, the first action to take is to simply reload the page. This minor step can often rectify temporary glitches in the CAPTCHA verification process. You can reload the page by pressing F5 on your keyboard or clicking the reload button in your browser. Sometimes the issue is just a fleeting error that can be resolved quickly.
Step 2: Check Your Internet Connection
A stable internet connection is crucial for CAPTCHA verification. Check if your connection is reliable and not experiencing any disruptions. If you notice any issues, try the following:
- Restart your router or modem to refresh the connection.
- Try connecting to a different network, if available.
- Ensure no other applications are consuming excessive bandwidth.
A solid connection may help eliminate the error you’re facing.
Step 3: Clear Browser Cache and Cookies
Over time, your browser collects data which may lead to issues with CAPTCHA responses. Clearing your cache and cookies can help resolve such problems. To do this, navigate to your browser’s settings and locate the options for clearing browsing data. It’s recommended to follow these steps:
- Select the time range for which you want to clear the data.
- Ensure both cache and cookies are checked, then confirm the action.
- Restart your browser after clearing the data.
Performing these actions can often correct any underlying issues associated with CAPTCHA failures.