Thanks for reaching out. Maybe it's just the formatting here on the Helpdesk, but there appears to be a blank line between your header line and the first data row. Is this the case?
Other potential issues can be if in further rows there are a different number of columns (by accident), or special/invalid characters, or even unexpected white space after a comma.
If these general hints don't fix it for you, would you mind sending your csv file as an email attachment to datalab@noirlab.edu (please reference this Helpdesk post) so that we take a closer look?