There is an error to install the app, but why is that?

I clicked on the link because I got a text message asking me to check my card usage.

App installation appears and I want to install the app. Why is it like that?

Installation Block

For security reasons, installation of applications provided by other sources other than the Play Store has been blocked. To change the settings, go to Sourcing > Lockdown Screen and Security > Unknown Source Apps.

There is an explanation about what to do with the link, but I don't know because it's too complicated.

503 2017-03-11 Gentleman

A. 1

It's a phishing site where you lie about using a card.
You can just ignore it.

Gentleman 8 years ago 0

A. 2

There are so many such phishing that Google blocked the app from being installed outside of the official site for security reasons.
If you install it on your phone for the next test developed by the developer, the above settings may be necessary
There's nothing for ordinary people to use.
Just ignore it and delete the text kk

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