Receiver Rest Adapter - Operation POST

Hi Experts

I am  working on an interface with a receiver Rest adapter.

The below error comes up in SAP PI when I try to perform the POST operation on the URLs : https://wwww.cs21.my.salesforce.com/services/oauth2/token?grant_type=xxxxx&client_id=xxxxx&client_secret=xxxxxxxx&username=xxxxx&password=xxxxx.

The Error Message is "Exception caught by adapter framework: HTTP POST call to https://wwww.cs21.my.salesforce.com/services/oauth2/token?grant_type=xxxxx&client_id=xxxxx&client_secret=xxxxxxxx&username=xxxxx&password=xxxxx not successful. HTTP/1.1 400 Bad Request".

When I use the  POSTMAN app or SoapUI it works perfectly fine.

Please can you let me know what could be this issue.

Thanks,

Danisay Vujovic