"Authorization Required: Unauthorized" error while delivering document via https

I have installed a Self Signed certificate provided by the partner and trying to deliver data through HTTPS to partner via the TN.

But I see the below error in the TN

Delivery service failed with a status of fail and status message of com.wm.app.b2b.server.ServiceException: com.wm.net.NetException: [ISC.0064.9314] Authorization Required: Unauthorized

Can anyone please help me with what is going wrong.