Please, tell me if I'm doing something wrong. It's the third time I try to apply and nobody says nothing.
I'll tell you what I think: I have looked at your post history and I see that you write very little. From May 25th to June 10th you didn't write anything, and the post you wrote that day was to apply for this campaign. The next post was 4 days later to re-apply.
I don't know what Brainboss will think, as he is the manager and has the last word but in general a campaign manager will not like your post history. They usually want it to show that you regularly write decent posts.
Then I saw that you wrote a few posts yesterday. In my opinion if you continue like this, writing decent posts regularly, even 2 or 3 a day on average, you will increase your chances of being accepted in campaigns.