restricted access to SMBus extended on BQ3050

Hello

I cannot to change the value of RSNS (or other) in the SMBus extended, I am in full access and unsealed access (I have access to data flash).

When i want write or read at 0x71 i have this error :

I don't understand, because I have access to FET control (0x46) for example.

I try by the manufacturer access and in normal mode (like the picture).

Thanks