What behaviour is observed:

Skin at mojang acc did not change after /skin-upload, and Skin-ID dont work.

What behaviour is expected:

Just working skins.

Steps/models to reproduce:

/skin-upload [link], /skin-select [ID]

Plugin list:

ProtocolLib, ChangeSkin

Environment description

Spigot 1.12 R0.1

Plugin version or build number (don't write latest):

3.0

Error Log:

Hastebin / Gist link of the error or stacktrace (if any)

Configuration:

I think i dont need to show config, because in the console i saw successfully acc connect.
Hastebin / Gist link of your config.yml file

http://prntscr.com/i94u78 -> but skin has not changed
log: http://wklej.org/id/3360434/

Please use a dev-build.

I changed spigot and plugin to last dev build and now i have different error
http://wklej.org/id/3360443/ -> log

403 means forbidden which could mean incorrect credentials.

ok im generated new config and now acc is working but still skin is the same all time, and sometimes i see this error in the console:
http://wklej.org/id/3360445/

429 means too many requests within one minute

Now its working without errors but still skin is not uploading at mojang acc, after successful message

It's uploading the skin, downloads it and changes it back.

EDIT: ChangeSkin only needs the signature that it was hosted sometime at Mojang servers.

But why all ID's has the same signature, im uploading different skins

Do you checked the database? The signatures should change on every requests

http://prntscr.com/i958gw

I cannot see there that the signature is the same. It just shows the datatype, here a blob (binary large object -> binary data)

How can i check the signature?

Please post the server log