Juniper ACX1100-AC GRE tunnel configuration

Dear folks, I'm kind of a beginner with Junos, but I did all my homework and read their documentation thoroughly.

I was trying to setup a GRE tunnel between two sites, but the gr-0/x/x interface doesn't want to appear after configuration.

What am I doing wrong?

chassis { fpc 0 { pic 0 { tunnel-services { bandwidth 1g; } } } alarm { management-ethernet { link-down ignore; } } } interfaces { gr-0/0/10 { unit 0 { tunnel { source x.x.x.x; destination y.y.y.y; } family inet { address 10.0.240.9/30; } } } }