Problems exporting mixdown as 192 kbps MP3 – Adobe Support Community

Hi. I’m trying to export some book chapters as MP3s. However, the publisher needs these MP3s to be 192 kbps or higher. 

 When I try to export the mix at the right rate I get this error message: ‘The selected options cannot be used as the resulting format is not compatible with the session format.’

 I’m at a loss. Is there something I need to do with my audition session to be able to export it at the right kbps?