Why can't I upload my data from my phone

I am trying to build a survey in excel and upload it to CommCare. I have uploaded my survey, I started in Excel and then used this website (ODK - XLSForm Online) to convert it to an .xml file. When I tried to run the survey in the browser from the application dashboard, I got an error and I was unable to go through the survey. See the circled area in the uploaded picture for the error message.

I was able to get the survey to work on my phone and I can type in answers and go through each of the answers but when I try to save the data I get a message “Error Saving your Form Unknown Error”. Then all my answers in the CommCare form on my phone are erased.

I was able to build a DIFFERENT survey directly in the browser (just 3 questions to test the functioning), upload it to my phone, complete it in my phone, and download the data. So I suspect the issue is something to do with the excel file I am using.

Can anyone help me with the issue I am having? Thank You.

you imported a converted XLS form didn't you?