GPCR Flexible docking

Dear all

I'm trying to dock a GPCR receptor to its ligand (a chemochine)

I'm using flexible docking.

Here the steps I followed:

1) prepare GPCR model and minimized it

2) chemochine ligates to GPCR Nter, but we dont' know which are the residues involed. So I selected the first 30 residues at GPCR Nter and define a sphere

3) I selected the first 10 residues at chemochine Nter and define a sphere

Then I tried to carry out docking, but after a few second the protocol exit with this error:

No ligand poses were docked - please check output or log files

How can solve it ?

Thanks