fail to upload a world in Minecraft Realms getting error failed to upload (-1)

I need the launcher log to investigate more. Go to Development Console and copy the whole text here.

[07:18:05 INFO]: Minecraft Launcher 1.4.7 (through bootstrap 4) started on windows...
[07:18:05 INFO]: Current time is Jul 28, 2014 7:18:05 AM
[07:18:05 INFO]: System.getProperty('os.name') == 'Windows 8'
[07:18:05 INFO]: System.getProperty('os.version') == '6.2'
[07:18:05 INFO]: System.getProperty('os.arch') == 'x86'
[07:18:05 INFO]: System.getProperty('java.version') == '1.7.0_65'
[07:18:05 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[07:18:05 INFO]: System.getProperty('sun.arch.data.model') == '32'
[07:18:05 INFO]: JFX has been detected & successfully loaded
[07:18:05 INFO]: Refreshing local version list...
[07:18:05 INFO]: Refreshing remote version list...
[07:18:12 INFO]: Refresh complete.
[07:18:12 INFO]: Loaded 1 profile(s); selected 'charter_boat'
[07:18:12 INFO]: Refreshing auth...
[07:18:12 INFO]: Logging in with access token

is that what you are after?

This is the log before clicking on Play button, I need the logs when you do an upload and it fails. So simply when the upload fails go to Development console and copy the text.

Does this still affect the current version/snapshot 1.8.1/1.8.2-pre1? If so, please update the Affected Versions.

Confirmed as of 1.8.1.
Happened at ~ 45% of a 450 MB world:

[23:52:37] [Client thread/INFO]: Setting user: Kumasasa
[23:52:37] [Client thread/INFO]: (Session ID is token:d28b28df14a54c249b2cefd722b156fb:212c6adb6aad4b04ab210d52a98931c0)
[23:52:39] [Client thread/INFO]: LWJGL Version: 2.9.1
[23:52:43] [Client thread/INFO]: Reloading ResourceManager: Default, Misa Patch Les 1.8.zip, Misa.zip, XDBMisaPatchV1.4.zip
[23:52:43] [Client thread/WARN]: ResourcePack: ignored non-lowercase namespace: %s in %s
[23:52:44] [Sound Library Loader/INFO]: Starting up SoundSystem...
[23:52:44] [Thread-6/INFO]: Initializing LWJGL OpenAL
[23:52:44] [Thread-6/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[23:52:44] [Thread-6/INFO]: OpenAL initialized.
[23:52:44] [Sound Library Loader/INFO]: Sound engine started
[23:53:04] [Client thread/INFO]: Created: 2048x2048 textures-atlas
[23:53:18] [Client thread/INFO]: Realms library version == 1.7.8
[23:53:19] [MCO Availability Checker #1/INFO]: Realms is available for this user
Jan 28, 2015 12:24:56 AM org.apache.http.impl.execchain.RetryExec execute
INFORMATION: I/O exception (java.net.SocketException) caught when processing request to {}->http://54.247.179.189:8080: Connection reset by peer: socket write error
[00:24:56] [Thread-14/ERROR]: Caught exception while uploading: null
[00:27:43] [Client thread/INFO]: [CHAT] Screenshot gespeichert unter 2015-01-28_00.27.43.png

Can no longer confirm with 1.8.9 / Realms 1.7.59. Uploaded said world successfully.

It's failing for me in 1.11.2 with the same issue. Also after failing the realms server cannot be accessed. Whenever I try to reset the world or open/close the server it takes forever not accomplishing anything. I also can't play on the server for a while after as well.

Robert, this is happening to me too. It consistently fails at 9.5%, then the Realm won't upload.

Just an update, I tried again after half an hour and it worked. Might have been a server issue.

I've been trying it all day and still to no avail. It fails at 100% for me though, and when it is verifying the world.