Unable to launch the game in Offline Mode - Authorization Loop

[ReDoG]

I am reporting a major issue when trying to run IL-2 Sturmovik: Great Battles in Offline Mode.

Whenever I try to launch the simulator without an active internet connection, the game fails to start and displays the following errors:

• #1: No connection with authorization server.
• #2: Connection to master server temporarily lost. Check your internet connection.

There is a "Close" button below the message, but when I click it, the error simply pops up again immediately. It is impossible to bypass this screen, making the simulator completely unplayable offline.

I would like to know if this is a bug introduced in recent updates or a deliberate change by the developers. One of the key features of this sim has always been the ability to play offline.

Please, look into this and fix it. Many of us rely on being able to fly without a permanent internet connection.

Best regards.

Edited April 25 by ReDoG

[Alouicious]

I also would like help with this. Internet access is not always available, and it needs to work either way.

[LukeFF]

Please file a support ticket here: https://il2-series.com/en/support/

[Gutholz]

In addition, when there is no internet connection then an endless amount of messages will appear until the game almost freezes.

That is also visible in the screenshot by ReDoG. It is always the same two messages but repeated, it fills up the message window and then you can see from the scrollbar that it continues. After some moments the game almost freezes for me despite good PC (Ryzen 7 CPU) and it becomes difficult to click.

[Pinguim]

I also faced this issue. I didn't have internet connection and was planning on playing some quick missions, unfortunately not possible. I'm using the Steam client (Steam was in offline mode).

[LukeFF]

Yes, Steam now requires an online connection.

[CrawdadsRevenge]

On 5/5/2026 at 6:26 PM, LukeFF said:

Yes, Steam now requires an online connection.

Is this only for Steam or does the standalone also require a constant connection? 

[dryheat94]

6 hours ago, CrawdadsRevenge said:

Is this only for Steam or does the standalone also require a constant connection? 

Only Steam. The launcher will look for an update and fail when no online access. You must start the Il-2.exe directly and it will bypass the update check and the game will run offline.