Failed to check connectivity to the companion server: System.NullReferenceException: Object reference not set to an instance of an object
at Steamworks.SteamServer.get_PublicIp () [0x00005] in <f5d7d7739132426c8fbaa834c665b689>:0
at ConVar.App.GetPublicIP () [0x00029] in <ae9b6b0055f942fd9e6fca4c8270053c>:0
at ConVar.App.GetPublicIPAsync () [0x0003c] in <ae9b6b0055f942fd9e6fca4c8270053c>:0
at CompanionServer.Server.CheckConnectivity () [0x00094] in <ae9b6b0055f942fd9e6fca4c8270053c>:0
Setting breakpad minidump AppID = 252490
SteamInternal_SetMinidumpSteamID: Caching Steam ID: 76561197960265728 [API loaded no]
This error appeared to me.