Your header line does not match those in the examples. Scroll down on the form to the help section for the details, including linked example inputs.
The https://huttenhower.sph.harvard.edu/galaxy/ public Galaxy server hosts customized versions of the
LefSe tools. If you need more help than a tool form provides, contact the server support team directly. This particular server’s support/admin team do not track this forum as far as I know.
Contact information for public Galaxy server’s is usually on the home page of the server and/or here: https://galaxyproject.org/use/.
For this server, the contact email is at both places. The problem could be due to 1) input header format or 2) tool/server-side issue (possibly known or unknown). The former seems more likely in this case, so I would suggest reviewing/reformatting based on that information first, then contact them after if problems persist.
Server “welcome” home page:
If you have any comments, questions, or suggestions, please contact Dr. Huttenhower.
Server directory info page at the /use link, above. See the section “User support”.