The authorization and session tokens start with 1%2F and the percent sign gets stripped by the regex patterns.
Update the regex patterns in the auth() function of the blogger-importer.php plugin:
Line 99: Added percent sign in regex pattern for authorization token
$token = preg_replace( '/[^%-_0-9a-zA-Z]/', '', $_GET['token'] );
Line 108: Added percent sign in regex pattern for session token
preg_match( '/token=([%-_0-9a-z]+)/i', $response, $matches );
That worked for me.
