ERROR_ONLY_IF_CONNECTED - 1251 (0x4E3)
This operation is supported only when you are connected to the server.
Updated: Feb 21, 2026
Introduction
The ERROR_ONLY_IF_CONNECTED error code, represented by the numeric value 1251 or its hexadecimal equivalent 0x4E3, indicates that a particular operation is only supported when the system is connected to a server. This article provides an in-depth explanation of this error and how developers should interpret it.
Technical Meaning
The ERROR_ONLY_IF_CONNECTED code is returned by Windows APIs when attempting to perform operations that require a connection to a server, but such a connection is not established at the time of the operation. This error typically occurs in scenarios where network-dependent services or functions are invoked without an active network session.
Error Details
The ERROR_ONLY_IF_CONNECTED code is a generic error type and does not provide specific details about the nature of the operation that requires a connection. It serves as a broad indication that the current operational context does not meet the required conditions for the requested action to proceed successfully.
Usage Context
This error can be encountered in various scenarios, such as when attempting to access remote resources, perform network-dependent operations, or execute functions that rely on server-side data. The exact operation that triggers this error will depend on the specific API being used and the context in which it is invoked.
Developer Interpretation
When encountering ERROR_ONLY_IF_CONNECTED, developers should ensure that their application has established a valid connection to the required server before attempting the operation. This may involve checking network connectivity, ensuring that necessary authentication steps have been completed, or confirming that all prerequisites for the operation are met.
Related Errors
- ERROR_CONNECTION_REFUSED (10061): Indicates that the remote host actively refused an attempted connection.
- ERROR_NO_SUCH_SERVER (20598): The specified server does not exist or is not available.
- ERROR_NETWORK_UNREACHABLE (67): A required network is unreachable.
FAQ
Q: What causes ERROR_ONLY_IF_CONNECTED?
A: This error occurs when the operation requires a connection to a server, but no such connection exists at the time of invocation. Common causes include missing network connectivity or unmet prerequisites for the operation.
Q: How can I resolve this issue?
A: Ensure that your application has established a valid connection to the required server before performing the operation. Check network status and any necessary authentication steps.
Summary
The ERROR_ONLY_IF_CONNECTED error code is a generic indication that an operation requires a server connection, but one is not available at the time of invocation. Developers should ensure proper network conditions and prerequisites are met to avoid this error and successfully execute operations that depend on server connectivity.