HTTP 423 Locked vs 511 Network Authentication Required
HTTP 423 (Locked) is a 4xx Client Error response, while 511 (Network Authentication Required) is a 5xx Server Error response. 423 indicates that the resource is locked and cannot be modified (WebDAV). In contrast, 511 means that the client needs to authenticate to gain network access. Used by captive portals (hotel/airport WiFi).
Description
The resource is locked and cannot be modified (WebDAV).
When You See It
When trying to edit a file that another user has locked in WebDAV.
How to Fix
Wait for the lock to be released, or request the lock owner to unlock it.
Description
The client needs to authenticate to gain network access. Used by captive portals (hotel/airport WiFi).
When You See It
When connecting to WiFi that requires login (airport, hotel, coffee shop).
How to Fix
Open a browser and complete the captive portal login process.
Key Differences
423 is a 4xx Client Error response, while 511 is a 5xx Server Error response.
HTTP 423: The resource is locked and cannot be modified (WebDAV).
HTTP 511: The client needs to authenticate to gain network access. Used by captive portals (hotel/airport WiFi).
You encounter 423 when when trying to edit a file that another user has locked in WebDAV.
You encounter 511 when when connecting to WiFi that requires login (airport, hotel, coffee shop).
When to Use Which
For 423 (Locked): Wait for the lock to be released, or request the lock owner to unlock it. For 511 (Network Authentication Required): Open a browser and complete the captive portal login process.