Connectivity Problem with American Truck Simulator - Main server port not listening for ATS

Don't know why, but after a couple of restarts it is working out of nothing.... Sorry for the ticket.

System Information

Field Value
Operating System Linux - Debian GNU/Linux 12 on x86_64
Product AMP ‘Phobos’ v2.6.2.4 (Mainline)
Virtualization Docker
Application American Truck Simulator
Module GenericModule
Running in Container Yes
Current State Ready

Problem Description

Issue

MAin Server Port stays on Not Listening.
Console output is: SteamInternal_SetMinidumpSteamID: Caching Steam ID: 76561197960265728 [API loaded no]

amp@debian:/$ ampinstmgr table
[Info/1] AMP Instance Manager v2.6.1.2 built 25/03/2025 13:01
[Info/1] Stream: Mainline / Release - built by CUBECODERS/buildbot on CCL-DEV
Instance Name │ Friendly Name │ Module │ IP │ Port │ Up
───────────────────┼──────────────────┼────────────┼─────────────────┼───────┼───
ADS01 │ ADS │ ADS │ amp.mrtank.de │ 8443 │ ✓
AmericanTruckSi… │ AmericanTruck… │ Generic │ 127.0.0.1 │ 8080 │ ✓

amp@debian:/$ ampinstmgr ports
[Info/1] AMP Instance Manager v2.6.1.2 built 25/03/2025 13:01
[Info/1] Stream: Mainline / Release - built by CUBECODERS/buildbot on CCL-DEV
Please enter value for Instance Name

AmericanTruckSimulator01

[Info/1] Port usage for AmericanTruckSimulator01 (AmericanTruckSimulator)
[Info/1] Instance is currently running.
[Info/1] LISTENING 8080 TCP (Core.Webserver.Port)
[Info/1] LISTENING 2224 TCP (FileManagerPlugin.SFTP.SFTPPortNumber)
[Info/1] CLOSED 27015 UDP (GenericModule.App.Ports.$MainServerPort)
[Info/1] LISTENING 27016 UDP (GenericModule.App.Ports.$QueryDedicatedPort)
amp@debian:/$ ampinstmgr dumpfirewall
[Info/1] AMP Instance Manager v2.6.1.2 built 25/03/2025 13:01
[Info/1] Stream: Mainline / Release - built by CUBECODERS/buildbot on CCL-DEV
[Error/1] No firewall manager available.
amp@debian:/$ ufw status
-bash: ufw: command not found

Reproduction Steps

  • create instance
  • port forwarding on router
  • add server files in ATS folder
  • add logon token in config and edit couple of config things like name and things
  • start server
  • Not Listening on Main Server Port ( SFTP and Query Dedicated Port are Listening)

Console output:

uset g_steam_screenshots “2”
uset g_artist_id “0”
uset g_save_format “0”
uset g_trailer_cables_mode “2”
uset g_intelligent_transmission “0”
uset g_spec_trans_refill_tank “1”
uset g_flyspeed “100.0”
uset g_online_loading_screens “-1”
uset g_news “-1”
uset g_lang_init “en_gb”
uset g_colbox “0”
uset g_radio_mode “2”
uset g_ignore_low_fps “0”
uset g_truck_light_specular “1”
uset g_gfx_all_scales “0”
uset g_gfx_advanced “0”
uset g_gfx_quality “-1”
uset g_hq_3d_scale “0.0”
uset g_hq_3d_screenshot “0”
uset g_menu_aa_limit “8”
uset g_additional_water_fov “20.0f”
uset g_water_reflect_actor “0”
uset g_rain_sensor “0”
uset g_rain_reflect_hookups “1”
uset g_rain_reflect_actor “1”
uset g_rain_reflect_traffic “1”
uset g_rain_reflect_cache “1”
uset g_rain_reflection “3”
uset g_reflection_scale “0”
uset g_reflection “3”
uset g_grass_density “2”
uset g_veg_detail “2”
uset g_save_indicator “1”
uset g_game_version “0”
uset g_force_online_lscrs “0”
uset g_hw_info “1”
uset g_glass_debugging_level “0”
uset g_line_sort “0”
uset g_cargo_sort “0”
*** WARNING *** : Unfinished data chunk detected!
Collecting prefab descriptors…
Loading prefab descriptors…
Loading ferry connections…
Loading cargo trailer assignment…
Loading company cargo assignment…
[physx] @0: Starting server.
[physx] @0: Creating reporter.
[physx] @0: Created foundation version 1.0.0.
[physx] @0: Created physics version 3.4.3.
[physx] @0: Initialized extensions.
[physx] @0: Created CPU dispatcher with 2 threads and logical CPU affinities:
[physx] @0: CPU 0 1 2 3
[physx] @0: thread 0 * * * *
[physx] @0: thread 1 * * * *
[physx] @0: Created convex cooking.
[physx] @0: Created fast triangle cooking.
[physx] @0: Created optimal triangle cooking.
[physx] @0: Creating simulation filter.
[bullet] Starting server
[physx] @0: Creating debug draw.
[MP] =========================================================================
[MP] Session automated start
[MP] -------------------------------------------------------------------------
[MP] DLC - us_arizona
[MP] DLC - us_idaho
[MP] DLC - us_nevada
[MP] DLC - us_nwmexico
[MP] DLC - us_oregon
[MP] DLC - us_utah
[MP] DLC - us_wa
[MP] MOD - Caterpillar C18 engine f
[MP] MOD - Volvo D16 Engine and ATO
[MP] MOD - Caterpillar C16 800 Twin
[MP] MOD - Hadley Airhorn Pack for
[MP] MOD - Realistic Rain v5.1
[MP] MOD - Real Soundproofing
[MP] -------------------------------------------------------------------------
[MP] Server init
Setting breakpad minidump AppID = 270880
SteamInternal_SetMinidumpSteamID: Caching Steam ID: 76561197960265728 [API loaded no]

What am I doing wrong?