FTP 125 Data Connection Open vs 550 File Unavailable
FTP 125 (Data Connection Open) is a 1xx Positive Preliminary response, while 550 (File Unavailable) is a 5xx Permanent Negative response. 125 indicates that the data connection is already open and the transfer is beginning. No need to open a new data connection. In contrast, 550 means that requested action not taken. File unavailable — the file does not exist, the path is wrong, or you do not have permission to access it.
Description
The data connection is already open and the transfer is beginning. No need to open a new data connection.
When You See It
When the server reuses an existing data connection for a file transfer instead of opening a new one.
How to Fix
No fix needed — the transfer is starting immediately. Your client should begin reading or writing data on the existing connection.
Description
Requested action not taken. File unavailable — the file does not exist, the path is wrong, or you do not have permission to access it.
When You See It
When you try to download, delete, or navigate to a file or directory that does not exist or is restricted by server permissions.
How to Fix
Verify the file path and name are correct (FTP paths are case-sensitive on most servers). Check your user permissions with the server administrator.
Key Differences
125 is a 1xx Positive Preliminary response, while 550 is a 5xx Permanent Negative response.
FTP 125: The data connection is already open and the transfer is beginning. No need to open a new data connection.
FTP 550: Requested action not taken. File unavailable — the file does not exist, the path is wrong, or you do not have permission to access it.
You encounter 125 when when the server reuses an existing data connection for a file transfer instead of opening a new one.
You encounter 550 when when you try to download, delete, or navigate to a file or directory that does not exist or is restricted by server permissions.
When to Use Which
For 125 (Data Connection Open): No fix needed — the transfer is starting immediately. Your client should begin reading or writing data on the existing connection. For 550 (File Unavailable): Verify the file path and name are correct (FTP paths are case-sensitive on most servers). Check your user permissions with the server administrator.