There are a bunch of different error codes and their
corresponding error messages that may appear under error
conditions. At the time of this writing, the exit codes are:
1 Unsupported protocol. This build of curl has no support
for this protocol.
2 Failed to initialize.
3 URL malformed. The syntax was not correct.
4 A feature or option that was needed to perform the desired
request was not enabled or was explicitly disabled at
build-time. To make curl able to do this, you probably
need another build of libcurl!
5 Couldn't resolve proxy. The given proxy host could not be
resolved.
6 Couldn't resolve host. The given remote host could not be
resolved.
7 Failed to connect to host.
8 Weird server reply. The server sent data curl couldn't
parse.
9 FTP access denied. The server denied login or denied
access to the particular resource or directory you wanted
to reach. Most often you tried to change to a directory
that doesn't exist on the server.
10 FTP accept failed. While waiting for the server to connect
back when an active FTP session is used, an error code was
sent over the control connection or similar.
11 FTP weird PASS reply. Curl couldn't parse the reply sent
to the PASS request.
12 During an active FTP session while waiting for the server
to connect back to curl, the timeout expired.
13 FTP weird PASV reply, Curl couldn't parse the reply sent
to the PASV request.
14 FTP weird 227 format. Curl couldn't parse the 227-line the
server sent.
15 FTP can't get host. Couldn't resolve the host IP we got in
the 227-line.
16 HTTP/2 error. A problem was detected in the HTTP2 framing
layer. This is somewhat generic and can be one out of
several problems, see the error message for details.
17 FTP couldn't set binary. Couldn't change transfer method
to binary.
18 Partial file. Only a part of the file was transferred.
19 FTP couldn't download/access the given file, the RETR (or
similar) command failed.
21 FTP quote error. A quote command returned error from the
server.
22 HTTP page not retrieved. The requested url was not found
or returned another error with the HTTP error code being
400 or above. This return code only appears if -f, --fail
is used.
23 Write error. Curl couldn't write data to a local
filesystem or similar.
25 FTP couldn't STOR file. The server denied the STOR
operation, used for FTP uploading.
26 Read error. Various reading problems.
27 Out of memory. A memory allocation request failed.
28 Operation timeout. The specified time-out period was
reached according to the conditions.
30 FTP PORT failed. The PORT command failed. Not all FTP
servers support the PORT command, try doing a transfer
using PASV instead!
31 FTP couldn't use REST. The REST command failed. This
command is used for resumed FTP transfers.
33 HTTP range error. The range "command" didn't work.
34 HTTP post error. Internal post-request generation error.
35 SSL connect error. The SSL handshaking failed.
36 Bad download resume. Couldn't continue an earlier aborted
download.
37 FILE couldn't read file. Failed to open the file.
Permissions?
38 LDAP cannot bind. LDAP bind operation failed.
39 LDAP search failed.
41 Function not found. A required LDAP function was not
found.
42 Aborted by callback. An application told curl to abort the
operation.
43 Internal error. A function was called with a bad
parameter.
45 Interface error. A specified outgoing interface could not
be used.
47 Too many redirects. When following redirects, curl hit the
maximum amount.
48 Unknown option specified to libcurl. This indicates that
you passed a weird option to curl that was passed on to
libcurl and rejected. Read up in the manual!
49 Malformed telnet option.
51 The peer's SSL certificate or SSH MD5 fingerprint was not
OK.
52 The server didn't reply anything, which here is considered
an error.
53 SSL crypto engine not found.
54 Cannot set SSL crypto engine as default.
55 Failed sending network data.
56 Failure in receiving network data.
58 Problem with the local certificate.
59 Couldn't use specified SSL cipher.
60 Peer certificate cannot be authenticated with known CA
certificates.
61 Unrecognized transfer encoding.
62 Invalid LDAP URL.
63 Maximum file size exceeded.
64 Requested FTP SSL level failed.
65 Sending the data requires a rewind that failed.
66 Failed to initialise SSL Engine.
67 The user name, password, or similar was not accepted and
curl failed to log in.
68 File not found on TFTP server.
69 Permission problem on TFTP server.
70 Out of disk space on TFTP server.
71 Illegal TFTP operation.
72 Unknown TFTP transfer ID.
73 File already exists (TFTP).
74 No such user (TFTP).
75 Character conversion failed.
76 Character conversion functions required.
77 Problem reading the SSL CA cert (path? access rights?).
78 The resource referenced in the URL does not exist.
79 An unspecified error occurred during the SSH session.
80 Failed to shut down the SSL connection.
82 Could not load CRL file, missing or wrong format (added in
7.19.0).
83 Issuer check failed (added in 7.19.0).
84 The FTP PRET command failed.
85 Mismatch of RTSP CSeq numbers.
86 Mismatch of RTSP Session Identifiers.
87 Unable to parse FTP file list.
88 FTP chunk callback reported error.
89 No connection available, the session will be queued.
90 SSL public key does not matched pinned public key.
91 Invalid SSL certificate status.
92 Stream error in HTTP/2 framing layer.
93 An API function was called from inside a callback.
94 An authentication function returned an error.
95 A problem was detected in the HTTP/3 layer. This is
somewhat generic and can be one out of several problems,
see the error message for details.
96 QUIC connection error. This error may be caused by an SSL
library error. QUIC is the protocol used for HTTP/3
transfers.
XX More error codes will appear here in future releases. The
existing ones are meant to never change.
