You must specify a Primary Receiver (Email1).
EZChain Button settings can be specified either inside the saved Button or passed in the URL, but not both. Settings passed in via the URL must first be stored as 'Dynamic' in the Button Generator. For security reasons you should save as many settings as possible in the saved button, and only pass settings in via the URL that are dynamic and cannot be known in advance. Most often, dynamic settings will include ItemName, ItemPrice, and occasionally ReturnURL. Recipients may sometimes need to be dynamic as well. Most settings can be dynamic if needed (for maximum flexibility), but this opens up more opportunities for URL tampering. Any settings not marked as 'Dynamic' cannot be tampered with, because they cannot be passed in via the URL.
Review the Settings Guide for details about each setting, and for help in generating a button/URL with dynamic settings.