"Dark it Mail" App is an adjunct of the main "Dark it" App made in order to properly work with e-mail in the main Dark it App.
To work and access the e-mail properly on the Dark It mode, the user also needs to download the Dark it Mail app too. First the user must download Dark it App and then Dark it Mail app. Once the download of Dark it Mail app is done, the access to the e-mail is made regularly in the main Dark it App on the e-mail icon.
Therefore theres never a need to open Dark it Mail app, just download it after download the main Dark it App, and the e-mail with the Dark it mode is accessed in the main Dark it App.