X-zte-cause

When a network device manufactured by ZTE processes a request—whether it is a user trying to log in to a router admin panel, a device connecting to a carrier network, or an API call passing through a gateway—the device may append the x-zte-cause field to the communication. This field usually contains a numeric or alphanumeric code that signifies why a specific action occurred, or more commonly, why it failed.

HTTP/1.1 403 Forbidden Content-Type: text/html X-ZTE-Cause: 1001 x-zte-cause

The header is typically inserted into SIP response messages (such as 403 Forbidden ) when a network element encounters an active error. When a network device manufactured by ZTE processes

The most common instance of "x-zte-cause" appears during login failures. Standard HTTP codes like 401 Unauthorized or 403 Forbidden are vague. They tell you that you can’t come in, but not why . The most common instance of "x-zte-cause" appears during

responses when a user equipment (UE) fails to register. The header may reveal that the failure was due to an SBC policy or a specific CSCF internal state. Call Drops and Cancels:

A typical log entry might look something like this: