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❗ Error Codes#

This page documents common error codes returned by the CapMonster Cloud API along with their meanings and possible solutions.

🔐 Authentication & Authorization#

ERROR_KEY_DOES_NOT_EXIST#

Invalid API Key
The authorization key provided is not recognized or is in the wrong format.
→ Check your API key from the CapMonster Dashboard.

ERROR_ZERO_BALANCE#

No Funds
Your account balance is zero.
→ Add credits to continue solving captchas.

ERROR_IP_NOT_ALLOWED#

IP Not Allowed
Requests from your current IP address are not allowed.
→ Add your IP to the trusted list in your account settings.

ERROR_IP_BANNED#

IP Banned
Too many failed requests with incorrect API key from your IP.
→ Verify your key, wait a few minutes, and try again.

ERROR_IP_BLOCKED#

Your IP is Blocked
Your IP is permanently blocked due to repeated violations or suspicious activity.
→ Contact CapMonster support.

🖼️ CAPTCHA File Issues#

ERROR_TOO_BIG_CAPTCHA_FILESIZE#

Captcha Image Too Large
The image size exceeds 500 KB.
→ Compress or resize the image before submitting.

ERROR_ZERO_CAPTCHA_FILESIZE#

Captcha Image Too Small
The image size is less than 100 bytes.
→ Ensure the image is valid and properly encoded.

ERROR_CAPTCHA_UNSOLVABLE#

Captcha Unsolvable
The image may be too noisy, corrupted, or unsupported by the service.
→ Try another image or adjust your task.

🕓 Timing & Task States#

ERROR_NO_SUCH_CAPCHA_ID / WRONG_CAPTCHA_ID#

Captcha ID Not Found
No task found for the given ID, or the request was made after it expired.
→ Poll results within 5 minutes of task creation.

CAPTCHA_NOT_READY#

Captcha Not Ready
The task is still being processed.
→ Retry after 1–2 seconds.

ERROR_RECAPTCHA_TIMEOUT#

ReCAPTCHA Timeout
Task solving took too long, possibly due to slow proxy or server issues.
→ Use a faster proxy or adjust timeout settings.

🌐 Domain & SiteKey Errors#

ERROR_DOMAIN_NOT_ALLOWED#

Domain Blocked
CapMonster Cloud does not support solving captchas for the specified domain.
→ Use a different domain or provider.

ERROR_RECAPTCHA_INVALID_SITEKEY#

Invalid SiteKey
The specified websiteKey is not valid.
→ Double-check the data-sitekey on the target page.

ERROR_RECAPTCHA_INVALID_DOMAIN#

Invalid Domain
The domain doesn’t match the sitekey's origin.
→ Ensure both belong to the same origin.

ERROR_TOKEN_EXPIRED#

Token Expired
The challenge token has expired.
→ Create a new task with a fresh token.

📦 Task Definition Errors#

ERROR_NO_SUCH_METHOD#

Incorrect Method
The specified task type (in type) is invalid or unsupported.

ERROR_TASK_NOT_SUPPORTED#

Incorrect Task Type
The task format is not recognized.
→ Review the type value and match it to the correct schema.

ERROR_TASK_ABSENT#

Missing Task Object
No task object was provided, or the JSON is malformed.

ERROR_WRONG_USERAGENT#

Invalid User-Agent
The specified User-Agent string is no longer accepted.
→ Update to a current, valid browser UA string.

🌐 Proxy Errors#

ERROR_PROXY_CONNECT_REFUSED#

Proxy Connection Failed
Unable to reach proxy server.
→ Test your proxy or replace it.

ERROR_PROXY_BANNED#

Proxy Banned
The proxy IP is blocked by the target captcha provider.
→ Rotate your proxy or try a different provider.

⚠️ Service Load & Rate Limits#

ERROR_TOO_MUCH_REQUESTS#

Too Many Result Polls
You polled for the task result too frequently.
→ Wait at least 2 seconds between requests.

ERROR_NO_SLOT_AVAILABLE#

No Free Servers
All recognition servers are currently busy.
→ Retry after a short delay.

Warning

These error codes are related to Capmonster.cloud and not created by us.

You can reach the latest version from here.