Multi context "setting not found" error

Hello i'm on modx cloud so no database access, i use 2.2.6 version.
The cache is empty, cache_db is set to No.
I'm trying to get multi context working for multi site.
So i duplicate a context i create a new setting :

key : site_start
Name : Accueil du site
Value : 196

While it validates, a message error display "setting not found".
There is no specific language, it is french or english.
Did somebody already experienced something like that ?

I can give access to manager by PM.

Thank you very much.