Negotiating with Goblins
Syrma will tell you about his plan but it requires a book that currently resides in the library which the goblins have made their home.
The Goblin Library is located to the south of the barrows where you first came out from. Fast travel there and head south.
Before you enter the territory, Coren will say a few things about the place and goblins.
Make your way through the many goblins scattered around to get to the entrance of the library. Enter it.
When you enter, you will find a lively place in which a lot of goblins live.
Speak to Krokus and get through by however you wish and also complete the quest.