Setting up a CS: Source server to be accessible from the internet

I am trying to set up a Counter-Strike: Source server so that I can play online with my friends. The server is simply a Windows 10 Desktop PC.

I followed the instructions using steam.cmd, as per here and here.

Now, when I execute C:\steamcmd\css\srcds.exe -console -game cstrike -insecure +maxplayers 16 +map de_dust2, a window opens and the following is displayed:

66.7 fps 0/16 on map de_dust2 Console initialized. Using Breakpad minidump system. Version: 5394425 AppID: 232330 Loaded 1335 VPK file hashes from C:\steamcmd\css\cstrike\cstrike_pak.vpk for pure server operation. Loaded 1335 VPK file hashes from C:\steamcmd\css\cstrike\cstrike_pak.vpk for pure server operation. Loaded 1218 VPK file hashes from C:\steamcmd\css\hl2\hl2_textures.vpk for pure server operation. Loaded 574 VPK file hashes from C:\steamcmd\css\hl2\hl2_sound_vo_english.vpk for pure server operation. Loaded 383 VPK file hashes from C:\steamcmd\css\hl2\hl2_sound_misc.vpk for pure server operation. Loaded 446 VPK file hashes from C:\steamcmd\css\hl2\hl2_misc.vpk for pure server operation. Loaded 5 VPK file hashes from C:\steamcmd\css\platform\platform_misc.vpk for pure server operation. server.dll loaded for "Counter-Strike: Source" maxplayers set to 16 Unknown command "r_decal_cullsize" maxplayers set to 16 Network: IP 192.168.178.28, mode MP, dedicated Yes, ports 27015 SV / 27005 CL Initializing Steam libraries for INSECURE Internet server. Authentication and VAC not requested. No account token specified; logging into anonymous game server account. (Use sv_setsteamaccount to login to a persistent account.) Executing dedicated server config file server.cfg Using map cycle file 'cfg/mapcycle_default.txt'. ('cfg\mapcycle.txt' was not found.) Set motd from file 'cfg/motd_default.txt'. ('cfg/motd.txt' was not found.) Set motd_text from file 'cfg/motd_text_default.txt'. ('cfg/motd_text.txt' was not found.) SV_ActivateServer: setting tickrate to 66.7 "bot_allow_machine_guns" = "1" game replicated - If nonzero, bots may use the machine gun. 'sourcemod/sourcemod.cfg' not present; not executing. Server is hibernating Connection to Steam servers successful. Public IP is 87.XX.XXX.XX. Assigned anonymous gameserver Steam ID [A:1:3375420425:14562]. VAC secure mode disabled. 

In particular, sourcemod/sourcemod.cfg not present; not executing. intrigues me (line 6 from the bottom).

Does this mean the server is not running?

When I open the game and search for the server using the indicated public IP and the ports 27015, 27005 etc., it says: "Server is not responding". On my router, I opened ports 26900 - 27020, which should cover the necessary range as per here.

When connecting using the PC's local IP, the server is found in the server list.