Permission not granted to push my patch

Hello,
I would like to push dictionaries on the dictionaries branch on Gerrit.
But when I try to push I have an issue with permission:
git push ssh://lafricain@gerrit.libreoffice.org:29418/dictionaries
HEAD:kikongo
Enter passphrase for key '/home/cyrille/.ssh/id_rsa':
Décompte des objets: 13, fait.
Delta compression using up to 4 threads.
Compression des objets: 100% (12/12), fait.
Écriture des objets: 100% (13/13), 14.10 KiB | 4.70 MiB/s, fait.
Total 13 (delta 1), reused 0 (delta 0)
remote: Resolving deltas: 100% (1/1)
remote: Processing changes: refs: 1, done   
To ssh://gerrit.libreoffice.org:29418/dictionaries
 ! [remote rejected] HEAD -> kikongo (prohibited by Gerrit)
error: impossible de pousser des références vers
'ssh://lafricain@gerrit.libreoffice.org:29418/dictionaries'

  I tried also with HEAD:refs/for/kikongo

How to create ref with permissions?

Thanks for help.