Hello Murthy,
I found the solution.. in my case, backend´s guys had not implemented "DELETE" http method and the plugin tries to look (unsuccessfully) to get this method (as a standard way in REST apps) and it did not find it.. From backend implemented a empty method and it was enough.
Of course, it is necessary to follow oData protocol line by line and it will works...
Here you can see another example of this problem, more or less similar...
Kapsel Offline OData - Flush works, but doesn't clear sap.islocal() flag
In this post I had written comments with the user Dan Antonio.
I expect you find the solution..