HTTP 403 when uploading binary file to Azure Storage Account using PO 7.5 REST Adapter

I'm encountering an HTTP #403 when trying to upload a ZIP file to Azure Blob storage using the PO 7.5 REST receiver channel and an HTTPS PUT request to the container. I'm authenticating with SAS token that I'm passing in the URL

Error Message:

"Server failed to authenticate the request. Make sure the value of authorization header is formed correctly including the signature"

URL pattern:

https://MyAccount.blob.core.windows.net/MyContainer/{filename}?sv=2019-02-02&ss=bfqt&srt=sco&sp=rwdlacup&se=2021-04-02T20:35:28Z&st=2020-04-03T12:35:28Z&spr=https&sig=MySASInfoHere

The Blobname is passed to placeholder {filename} dynamically via DynamiConfiguration bean, but I have tried setting a static name, too, without success.

I have set the correct Blog type header.

The request is working perfectly fine in Postman. The SAS Token is not restricted to a particular IP range at this point.

Any pointers?