How to fetch attachment issue

Error: JIRA REST API returns java.lang.RuntimeException: Failed : HTTP error code : 404

I am using Smart attachment plugin 2.2.2 version and I am developing Meta Validation Plugin and that using URI “” +issue for getting the issue ids. I am trying to use the JIRA rest API to get the issue is moved on one transition to another.
And I am using Jira is 7.13.0.!

Smart Attachments 2.X no longer supports REST API, only Java API. Please drop an email at with description of what you want to do.

Sincerely, Vadim