Every action on my repository trigger this error:

Command:
-c color.ui=false -c core.quotepath=false -c core.pager=cat -c core.editor=: -c credential.helper=C:/Users/Rafael Dominiquini/AppData/Local/ungit/resources/app.asar/bin/credentials-helper 0 8448 origin ls-remote --tags origin

Error:

git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

OS: Windows 10 x64
UNGIT VERSION: 1.5.24

Thanks