Unable to create a fillable pdf form

I tried to upload one of my pdf forms to convert it to fillable form but I received a email saying the import failed. What can I do to make it import.

You can try to import it once again. If it does not help, I am afraid that we are unable to import your PDF(s).

Please note that imported PDFs cannot work as web forms.

You might consider re-creating the form using our drag and drop form builder. In this case you will be able to use the form as a web form and fillable PDF at the same time.