My phone works fine but every time i boot it up or restart it, it shows a yellow triangle. How to fi

[AC Question]

I have a samsung galaxy On7 Sm-G6000 Chinese version. In my phone my settings icon has a 1 at the top of it and when i go into settings to see what its about in the 'About Phone'- 'System Status' tab it says my phone operating system has been modified etc. What is wrong , how to fix ? My phone works fine but every time my phone boots up or restarts it has a yellow triangle with chinese writing by it. How to fix?