How to solve CaptchaFox on signup.mail.com

Introduction

If you are integrating automatic CaptchaFox captcha solving for mail.com and facing token rejections due to a missing MAM_ prefix, this guide is for you.

The 2Captcha service supports solving CaptchaFox via API v2 with the apiServer parameter. This is critical for sites with custom infrastructure where the token format depends on the widget source.

This material provides general recommendations for configuring requests, analyzing the page, and debugging integration using mail.com as an example.

General Information

CaptchaFox is a tokenized protection system with interactive tasks (often sliders) and behavioral analysis. For mail.com, a custom version with its own API server is used, which affects the format of the returned token.

CaptchaFox Features for mail.com

Why the apiServer Parameter Is Critical

If you do not specify apiServer or pass an incorrect value, 2Captcha workers will use the default endpoint https://cdn.captchafox.com/. As a result, a standard token without the MAM_ prefix is returned, which mail.com rejects with an HTTP 424 error.

Environment Setup

Before you start, make sure you have:

• Access to the 2Captcha API - an API key from your account dashboard
• A residential proxy - with geolocation matching the target site (for mail.com: GB, DE, or US)
• An up to date User-Agent - a string from a real browser that is making the request
• Debugging tools - a browser with DevTools, an HTTP client (curl, Postman, or a library in your language)

Proxy Requirements

Page Analysis and Parameter Extraction

Detecting the Captcha

On the registration page https://signup.mail.com, the CaptchaFox captcha appears when creating a new account. Visually, it is a slider with the CaptchaFox logo.

Finding the websiteKey

1. Open DevTools (F12) on the target page
2. Go to the "Elements" or "Sources" tab
3. Find the script that loads CaptchaFox, or search for sk_

Example tag:

<script src="https://s.uicdn.com/mampkg/@mamdev/core.frontend.libs.captchafox/api.js?key=sk_ILKWNruBBVKDOM7dZs50WPNUuCUKR"></script>

The value of the key parameter is your websiteKey.

Analyzing Network Requests

1. In the "Network" tab, filter requests by captchafox
2. Find requests to challenge or verify
3. Record:
   • The full endpoint URL
   • Request headers (especially User-Agent, Origin, Referer)
   • The structure of the request and response body

This data will help you correctly form a task for 2Captcha.

Implementation

CaptchaFoxTask Structure

The task is sent via the createTask method to the endpoint https://api.2captcha.com/createTask.

Required task fields:

Example Request Body (JSON)

{
  "clientKey": "YOUR_API_KEY",
  "task": {
    "type": "CaptchaFoxTask",
    "websiteURL": "https://signup.mail.com",
    "apiServer": "https://s.uicdn.com/mampkg/@mamdev/core.frontend.libs.captchafox/",
    "websiteKey": "sk_ILKWNruBBVKDOM7dZs50WPNUuCUKR",
    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36",
    "proxyType": "http",
    "proxyAddress": "1.2.3.4",
    "proxyPort": 8080,
    "proxyLogin": "login",
    "proxyPassword": "password"
  }
}

Getting the Result

After creating the task, use the getTaskResult method to poll the status:

{
  "clientKey": "YOUR_API_KEY",
  "taskId": 123456789
}

Possible values for the status field:

Token Verification

After receiving the response, always check:

1. The presence of the solution.token field
2. The presence of the MAM_ prefix at the start of the token
3. That the token meets the target site requirements

Example validation (pseudocode):

if token starts with "MAM_":
    send token to mail.com
else:
    log error and send reportIncorrect

Parameter Explanations

The apiServer Parameter

• Specify as the full URL path to the JS file or the custom API domain
• For mail.com, use: https://s.uicdn.com/mampkg/@mamdev/core.frontend.libs.captchafox/
• An incorrect value leads to receiving a token without the MAM_ prefix

Proxy and Geolocation

• Without a proxy, the CaptchaFox task will not be accepted
• The proxy geolocation must match the target site
• Use residential proxies to minimize the risk of blocking

User-Agent

• Must match the browser making the request
• It is recommended to copy the current string from a real browser
• A mismatch can lead to token rejection on the mail.com side

Feedback on Solving Results

After testing the token on the target site, it is recommended to send feedback.

If the Site Rejected the Solution

Send a POST request to the reportIncorrect endpoint:

Endpoint: https://api.2captcha.com/reportIncorrect

Method: POST

Content-Type: application/json

Example request:

{
   "clientKey": "YOUR_API_KEY",
   "taskId": 74455221488
}

Example response:

{
    "errorId": 0,
    "status": "success"
}

Important: Do not use this method if your success rate is close to 0 percent. This may indicate an error in your code, not in the captcha solutions.

If the Site Accepted the Solution

Send a POST request to the reportCorrect endpoint:

Endpoint: https://api.2captcha.com/reportCorrect

Method: POST

Content-Type: application/json

Example request:

{
   "clientKey": "YOUR_API_KEY",
   "taskId": 74455221488
}

Example response:

{
    "errorId": 0,
    "status": "success"
}

Refund Policy

• Each case is reviewed individually
• For standard captchas, the correctness of the response is checked
• For token based captchas, worker statistics are analyzed
• Refunds are not guaranteed for every complaint
• The final refund amount may differ from the number of claims

Send reports honestly and only after real verification on the target site.

Requirements for a Custom apiServer

If you are using your own server for CaptchaFox, make sure it meets the following requirements:

Common Errors and How to Fix Them

Debugging Recommendations

• Enable detailed logging of requests and responses
• Save the taskId for each request, this will simplify support inquiries
• Test the integration in non-headless mode before launching in production
• Check the target site response after sending the token

Additional Resources

• CaptchaFox API v2 Documentation
• reportIncorrect Method - Report an incorrect solution
• reportCorrect Method - Report a correct solution
• Code Examples on GitHub
• Contact Support

Checklist

• Correct apiServer specified: https://s.uicdn.com/mampkg/@mamdev/core.frontend.libs.captchafox/
• websiteKey extracted from the page source code
• Proxy is configured and matches the target site geolocation
• User-Agent is current and matches the browser session
• All required fields are present in the request: proxyType, proxyAddress, proxyPort
• The received token is checked for the MAM_ prefix
• Logging is enabled for debugging
• Sending reportIncorrect and reportCorrect reports is implemented

Conclusion

Correct integration of CaptchaFox for mail.com requires accurate transmission of the apiServer parameter and compliance with proxy and User-Agent requirements. When using a custom API server, it is critical to ensure that 2Captcha workers receive and use the specified endpoint.

The apiServer parameter directly affects the token format. Only with the correct value will you receive a token with the MAM_ prefix that mail.com accepts.

Do not forget to send feedback via reportIncorrect and reportCorrect. This helps improve service quality and get refunds for incorrect solutions.

Automate any captchas with the 2Captcha API.