OKK collect error: " Document has no root element"

I am using the ODK collect for a data collection survey. there are different forms for capturing data and some capturing information with both audio and pictures. i was trying to edit some forms but on clicking "edit form" it brings the error " Document has no root element" . Some of the forms can be edited but for some the error appears. How can I be able to resolve this?

Hi @bnyerere
welcome to the forum! Please introduce yourself here!

when it comes to your question... could you attach your form?