Rated 5 out of 5 stars
Please Help, doesn't work. When i press mail merge it appears error message "invalid recipient address" and i can't go to the windows where i can choose the .csv file. Last May worked perfectly. Thunderbird v. 78.7.1 (64-bit) and mail merge v. 7.3.1
Found this solution: You must hit "Enter" or "Tab" once you have added the variable(s) in the To field.