@Dinesh Gudi As per the screenshot I can see that you are using the wrong request URI i.e. messages is missing in the URL
Please use the below request URI to send the message:
Syntax : http{s}://{serviceNamespace}.servicebus.windows.net/{queuePath|topicPath}/messages
ex : https://servicemax.servicebus.window.net/smx/messages
Further, I can see that you are passing the Content-Type as Application/Xml but it should be application/atom+xml;type=entry;charset=utf-8 as per the document.
Content-Type: application/atom+xml;type=entry;charset=utf-8
I have tested at my end and it is working as expected. Please update the URL and Content-Type and I hope it will resolve your issue.
Feel free to reach out to me if you are still facing the issue.
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