Sharepoint Online: DatefieldError

@Nanddeep: Sir, I have created this powerapp list form by using the option "Customize list form"  and not  "Create an app". I see only 1 screen with a form and there is no submit property in here. It was working fine but suddenly started displaying this error. I have also tried changing the "Defaultdate" property for the fields "StartDate" and "EndDate" to Now(), Today(), Parent.Default but is of no use.

 

Please advice.. 

 

Is this the right way to create listforms? 

Please check of StartDate and EndDate are being passed back to SharePoint on PowerApp form submit.

In the field properties, click Advanced and verify DataField