The application that implements Twitter login suddenly rejected that it did not work.

I'm not an engineer, but my fellow foreign engineer can't find a clue to the solution. Let me ask you a question.

Currently, I am implementing Twitter login with the iOS app I am running.
It was working as usual until now
I submitted an update to Apple the other day and received a reject.

The content was that if you tap Twitter login, an app called (Musica) will open.
We checked everything on the test flight and DEMO, but we couldn't confirm this phenomenon.

I have a question for those who understand or have experienced it, but what do you think is suspicious in this case?

In amateur opinion,
· API problems
·URL problem
·Virus
·Code problem
·Problem with Apple's device checking the application

I thought it was one of these, but our engineers said none of them were true.

If things go on like this, I will be in trouble because I can't update the app.
If anyone has similar experience or has any other ideas,
It would be very helpful if you could help me.

There is no problem with the technical response.I'm going to translate it into English and check with the engineer.

Supplement
login code:

TWTRTwitter.sharedInstance().logIn(){(session, error)in 
    iflet session=session{}
}

authentication:

let key=Bundle.main.object (forInfoDictionaryKey: "consumerKey"),
secret=Bundle.main.object(forInfoDictionaryKey: "consumerSecret")
iflet key = key as ? String, let secret=secret as?String, !key.isEmpty&!secret.isEmpty{
    TWTRTwitter.sharedInstance().start(withConsumerKey:key,consumerSecret:secret)
}