[ibr-dtn] bundle Put plain :ERROR 406

Hello Dears, I am trying to use bundle put plain command in two different machines (with eid registration) to save/send bundle but it gives me following error. however, I have followed api document formats like this: set endpoint xx bundle put plain Source: api:me Destination: dtn://ubuntu/xx1 (it is another machine which i have made regisetration of its endpoint) Blocks: 1 Flags: LAST_BLOCK Length: 4

helloworld *406 PUT FAILED*

*whats wrong?*