Find below the list of error codes and what you need to check to move on to the next step.
[CODE]: ENVELOPE_HAS_DUPLICATE_RECIPIENTS
This means that there are 2 or more contacts in the cover sheet that have the same email address. Envelopes can only be sent to a list of unique emails.
Please check contacts on the cover sheet for duplicate email addresses.
Note: If it's the same individual in the different contact cards, please use a different email address for one (i.e. personal email address).
[CODE]: INVALID_USERNAME_FOR_RECIPIENT
This means the name of one of contacts has either a space in the user name or an invalid character.
Please check contacts on the cover sheet for invalid characters or unnecessary spaces.