# Response Codes

These are the most common response codes you can get while using Oxylabs Datacenter Proxies.

<table><thead><tr><th width="166">Response code</th><th width="268.3177083333333">Error message</th><th>Description</th></tr></thead><tbody><tr><td><code>400</code></td><td><code>Bad Request</code></td><td>The request could not be understood. Please check if the request is formatted correctly.</td></tr><tr><td><code>403</code></td><td><code>Forbidden</code></td><td>Access denied: restricted target. Please contact support or your account manager if you have any questions.</td></tr><tr><td><code>404</code></td><td><code>Not Found</code></td><td>The domain specified could not be found or the resource is unavailable.</td></tr><tr><td><code>407</code></td><td><code>Proxy Authentication Required</code></td><td>User credentials are not provided / are incorrect / the user is connecting from an IP that is not whitelisted.</td></tr><tr><td><code>429</code></td><td><code>Too Many Requests</code></td><td>User has reached the thread/concurrent session limit.</td></tr><tr><td><code>500</code></td><td><code>Internal Server Error</code></td><td>We had a problem with our server. Try again later.</td></tr><tr><td><code>502</code></td><td><code>Bad Gateway</code></td><td>The proxy received an invalid response from the upstream or target server.</td></tr><tr><td><code>503</code></td><td><code>Service Unavailable</code></td><td>Failed to connect to the target server. DNS failure to resolve the target server address.</td></tr><tr><td><code>504</code></td><td><code>Gateway Timeout</code></td><td>A proxy server timed out, waiting for a response from the target server. It usually takes about 60s.</td></tr></tbody></table>


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