u/Beginning-Link445

I'm struggling to S rank the alt infiltrate grid 086 this is my current build for speed and stagger so I can pile drive the enemies but I can't seem to do it I'm only getting rank A. I'm cleaning the mission really quickly and taking very minimal damage. I also tried with the Ludlow smg but I couldn't get the S.

Why is the mail tab just infinitely loading? I can't claim some rewards because of this. It's happening on WiFi and Data.