PX4 SITL Stucks at Waiting for simulator to accept connection on TCP port 4562

Hello, I am trying to run px4 multi plane simulation on gazebo-classic.

This is my px4 command : PX4_SIM_MOEL=1031_gazebo-classic_plane_cam ./px4 -i 2

But it stucks at:

INFO  [px4] instance: 2
INFO  [px4] working directory /home/yigit/PX4-Autopilot/build/px4_sitl_default/rootfs/2

______  __   __    ___ 
| ___ \ \ \ / /   /   |
| |_/ /  \ V /   / /| |
|  __/   /   \  / /_| |
| |     / /^\ \ \___  |
\_|     \/   \/     |_/

px4 starting.

INFO  [px4] startup script: /bin/sh etc/init.d-posix/rcS 2
INFO  [param] selected parameter default file parameters.bson
INFO  [param] importing from 'parameters.bson'
INFO  [parameters] BSON document size 330 bytes, decoded 330 bytes (INT32:14, FLOAT:3)
INFO  [param] selected parameter backup file parameters_backup.bson
+ MAV_SYS_ID: curr: 4 -> new: 3
+ UXRCE_DDS_KEY: curr: 4 -> new: 3
INFO  [dataman] data manager file './dataman' size is 7872608 bytes
INFO  [init] PX4_SIM_HOSTNAME: localhost
INFO  [simulator_mavlink] Waiting for simulator to accept connection on TCP port 4562

The problem is Gazebo classic is not running itself automatically. Am i doing something wrong?