User Import says "Failed (see email)" but did not send me email

I’m trying to use the User Import function at User Import / Export Dashboard , but when I submit my file it says “Failed (see email).” However, I do not receive an email. Is there any way to track down what aspect of the process failed? I selected the Username-Password-Authentication database connection, and my json file looks like this example:

    "email": "",
    "email_verified": true,

Never mind! The problem was the extra comma in the json (after true). Thanks anyway!