Build Failed For iOS

I am getting below exception while running ionic cordova build ios.
The same project is working fine for Android. I am able to generate signed apk.

Seems something is wrong with something you use from Firebase.

What is your ionic info output?
What Firebase stuff are you using?

Here is my ionic info details.

Preformatted textIonic:

ionic (Ionic CLI) : 4.0.3 (/usr/local/lib/node_modules/ionic)
Ionic Framework : ionic-angular 3.9.2
@ionic/app-scripts : 3.1.11

Cordova:

cordova (Cordova CLI) : 8.0.0
Cordova Platforms : android 7.0.0, ios 4.5.5

System:

ios-deploy : 2.0.0
NodeJS : v8.11.3 (/usr/local/bin/node)
npm : 5.6.0
OS : macOS High Sierra
Xcode : Xcode 9.4.1 Build version 9F2000

Environment:

ANDROID_HOME : not set

I am using onesignal and firebase analytics (https://ionicframework.com/docs/native/firebase-analytics/) in the project.

Your dependencies look good, although for Android you might want to upgrade to a newer version of cordova-android. But that’s unrelated to you problem here.

@Sujan12 What can be the problem here?

A iOS header file is missing that should be there. Probably some problem when installing a plugin or library. I would deinstall them and follow their installation instructions again.

(Also: As you just posted a screenshot of the actual error message instead of a text string, we can’t google for the error message)