What switch? What router?
on the switch:
show int gi6/5 switchport
This will show you want operational mode has come up. But I would definitely be doing the sw mode acc anyway.
juniper configuration looks fine.

Thanks for help! It turned out, that this 1000BASE-T SFP was not supported(it wasn't original Juniper SFP)

Have you tried to connect your PC directly to the juniper router and ping it's ip-address.
Try this also with the switch. Maybe you can find the bastard that is given you so much trouble.