Sim card problem

I have just received the phone this Friday the 9th of October. Today, when I turned on my phone after work it said Sim card 1 is not installed but it works perfectly on slot 2. When i push the Sim card up and hold it on slot 1, it would work but when I let go of it, it doesn't detect it.

Zenfone 2 (4gb RAM, 64gb storage) ze551ml ZooAD