Why can't I open the audio-visual mail after I failed to rescue the heroine and received 15 at Shimen on July 28th?

This opening requires two conditions, one is the hero's fierce experience and Chris's three months, which is the alpha line, and the other is the hero's first failure, which is the beta line. These two conditions are the conditions for opening this email, and only these two can improve the SG line. After playing the game and reading the novel, you will know that this email was actually sent to you by the protagonist after SG (stans Gate Line) 15 years (I won't say that the protagonist on this line is also a tragedy). Why wasn't it intercepted by SCERN? Because the desperate town established by SERN can only appear on the Alpha line, but not on other lines. Please adopt it.