I tried to use mailmerge for customizing a series of emails. My database is a spreadsheet (but I tried with a CSV file as well) with the following fields: "firstname", "lastname" and "email". I put {{email}} in the "To:" field of the message and {{firstname}} in the body. However when I try to use mailmerge I receive an error message: "The address is not valid: please put a valid address in the "To:" field". If I put a valid address in the field (johndoe@mymail.com) and {{email}} in the BCC field, the messages are well composed (the first names are in the proper place) but, of course, the only generated email is addressed to johndoe and the fileld Bcc is simply ignored. It looks like Thunderbird does not accept {{email}} in the address fields but only in the body of the message. What can I do?