Does not display input form fields

Hello eveyone,
Can any one help me in displaying Camunda Form Input Fields,
I get “This task contains an external form to complete it. In order to open the external form click on the “Open external form” link below”. ( attached screenshot).

Can you check that your user task isnt with anything in the field “Form Key” in the “Form” tab in camunda modeler?
If you have any string set in this field, camunda will look for an external form instead of generate one.