Cannot delete field from form

Cannot delete field from form

I am trying to delete a field from a form and keep getting a pop-up error message "Delete operation faild.
 Please try after some time or refresh the page and try again." I've been trying since yesterday.

It seems from similar posts in this forum that this issue occurs from time to time and only the Zoho Support team can resolve it, so already granted Edit Access. The form is called Survey and the field to be deleted is called State (the single-line text field, not the Lookup drop-down). Thanks in advance.