No option for sychronization while creating a new collection

Hello,

I have LrC version 13.0.1 and for the first time I tried to create a new collection (not dynamic one) with the syncronisation option.

The problem I have is that when the options appear (after having selected "create new collection") the box that we are supposed to tick (synchronize with Lightroom) is not there (see screenshot).

And even after having created the collection, If I right click on it, no option relating to sync...

I don't know why !

PS : my adobe account is well active in the preferences and suscription is valid.

Does someone have an explanation to this issue and could help me to fix it ?

thanks