Why I can't lock messenger on Huawei p9 lite?

[AC Question]

I get new Huawei p9 lite 2017 and everything was working good until I wanted to lock Messenger. Other apps can be locked normaly but when I go to that settings or whatever it is Messenger icon is not there for lock up. So my question is: Is this problem on all Huawei p9 lite or am I doing something wrong? Thanks for your advices.