I couldn't upload the form because below problems

I couldn't upload the form because below problems.
http server error

Your file should have the .xlsx, .xml file extension because Ona uses XLS Forms to create forms.

Not sure what to do? Read more aboutUsing XLSForms

Hi @andargodk

A warm welcome to the ODK community and forums, please when you get a chance, introuce yourself and we would encourage you to use your picture an avatar it helps build community.

It sounds like you are using Ona as your server, you will get better support from the Ona team.

Make sure that your form uses the .xlsx format if you coding your forms using XLS Forms (Excel) or convert to .xml
.xls support was dropped, for background you go through this forum thread