Query returns results when executed from SFDC Console but returns empty array when same query is executed from from different salesforce apis

Question

I have executed this query directly from salesforce developer console

SELECT QualifiedApiName, Label FROM EntityDefinition where QualifiedApiName = 'Coupon'

And it returns data , but when i execute same query from my code it returns empty result

i have tried all these api clients

1. SfdcRestApi
2. SfdcMetadataApi
3. SfdcSoapApi
4. SfdcToolingApi

i get data in case of SfdcMetadataApi only but it does not return the label

I am using the same user in both cases