Marathon recently launched its PC testing phase on Steam and consoles. Players from Russia encountered the expected "tapir" error — it's formally impossible to play from this country (but Destiny 2 fans have long found solutions).
However, this is not the only problem. Russians and residents of other countries, including Western ones, were unable to break into Marathon due to a certain error "w:8:80090305".
Through experimentation, the community found the problem: it turned out that Marathon conflicts with Kaspersky. It is enough to press the "exit" button from the antivirus and restart the extraction shooter - the game should work.
In some cases, simply adding Marathon to the list of exceptions helps.