Exception when trying to access shared MailBox EWS 2013

Hello,

I'm trying to access a shared mailbox on a Exchange 2013 (office 365) with EWS but i have this exception :

"An unhandled exception of type 'System.TypeInitializationException' occurred in mscorlib.dll

Additional information: The type initializer for 'Exchange101.Email' threw an exception."

when i try this : service.AutodiscoverUrl(MySharedMailbox.Address, RedirectionUrlValidationCallback);

or this : FindItemsResults<Item> results = service.FindItems(MySharedMailbox.Address, view);

of course i'm authenticated with valid credentials to a mailbox that have access rights on the sharedMailBox

and i can read the informations about mails in my mailbox .

Can you help with this 

Thanks a lot.