# Response Codes

These are the most common response codes you can get while using Oxylabs Datacenter Proxies. If you receive any other response code, please contact your Dedicated Account Manager for more information.

<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>