We do see the "Command Line Argument" error message occur when quotation marks " " are used in the Invitation Email (this occurs with some email programs, not all, when using the "Preparer's Email Program" sending method). You will need to change the quotation marks to single quotation marks ' ' prior to being able to invite your client to sign: Wolters Kluwer logo-> Administrative Tasks-> Portal/Workflow-> Global Email Settings-> Edit next to "Default Signer Email"-> Replace " " marks with ' ' marks-> Save Template-> Return to your company/plan-> Invite Signer-> Click to Open Email and the email should open.