react native run ios not building

1react-native run-ios --device
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3this is for connected devices
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6react-native run-ios --simulator="simulator name"
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8or 
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10react-native run-ios --simulator
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1follow these steps its working for me
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3The platform version in your PodFile 
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5should be more then 11.0
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8and another main poin create a new file in your ios folder with any name 
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10my file rt.swift
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13inside file
14//
15//  rt.swift
16//  AwesomeProject
17//
18//  Created by Apple on 05/05/21.
19//
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21import Foundation
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24=================================================================
25after that remove pod folder and podfile.lock file  from ios folder then
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27RUN 
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29cd ios && pod install && cd .. && yarn ios
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