The four unchecked requirements shown in your screenshot are for completing specific Campaign Missions ([b]Charge[/b], [b]Commencement[/b], [b]Quarantine[/b] and [b]Gouge[/b]) at Mythic Tier; your visible game history suggests you have not done so. These Missions are separate from the Patrol Zone “Secret” Stragelets you have already collected and for which you have received credit. You can launch the four required Campaign Missions either when they come up in rotation for the Weekly Missions node or by interacting with their respective Campaign Banners found throughout Kepler. Once you have completed these Missions and deposited their Strangelets you then will be able to get credit for completing [b]the Message[/b] on Mythic in order to close out the Quest. (΄◉◞౪◟◉｀)

Did you also do all of the Mythic missions that you find on the map? Those would have a green square next to them if they were completed. Instead, in your screenshot, they have an empty black box.

According to your screenshot, you need to do the other 4 missions and collect their strangelets. (Notice only 1 of the 5 boxes is green) Then you'll progress to the next step. (Which is doing The Message on mythic)

Upvote.