invalid fullname, must end in a custom suffix ( for ex. __c )

I m getting error invalid fullname, must end in a custom suffix ( for ex. __c ) when deploying changes via Github (2 custom fields on , one on lead another on the Opportunity )to another sandbox.

Also verified the field names and api names too , it showing correct. Can anyone help me on this. 

#SalesforceDXCLI #SalesforceDeployment #Github #Salesforce