Submit Form Button not visible from distributed form

[csenor]

Good afternoon.  I'm unsure when this started happening, but I created a form and distributed it in Acrobat Pro DC.  How it is intended to work is that once complete, the user would see a purple ribbon at the top of the screen that says Submit Form.  For some reason, this ribbon is missing from the top of the page and I don't know why.  The form has been filled out over 60 times with no problem by other people.  I opened up the file in Tracker to see if the original file had changed.  The file appears fine, but is missing the purple ribbon at the top of the screen.  What would cause a distributed file to behave differently?  

Windows 10

[Amal.]

Hi Csenor 

Hope you are doing well and sorry for the trouble. As described the submit button is missing from the PDF form.

When you distribute a form, Acrobat automatically checks the form. If it doesn't find a submit button, it adds a Submit Form button to the document message bar. Users can click the Submit Form button to send completed forms back to you.

For more information about submit button, please check out the help page: https://helpx.adobe.com/acrobat/using/setting-action-buttons-pdf-forms.html#add_a_submit_button

Regards

Amal