as per the error says we need to go for

npm i lottie-ios@3.1.8 lottie-react-native@3.5.0 cd ios Pod install

issue Resolved

If you get something like this,

[!] CocoaPods could not find compatible versions for pod "lottie-ios":
  In Podfile:
    lottie-ios (from `../node_modules/lottie-ios`)

    lottie-react-native (from `../node_modules/lottie-react-native`) was resolved to 3.5.0, which depends on
      lottie-ios (~> 3.1.8)

Then we can resolve it by the following steps,

• Open terminal in root folder of your react native project.

• Execute the following commands to install lottie-ios and lottie-react-native packages with the specified version of the cocoa pod error.

  npm install lottie-ios@3.1.8 
  npm install lottie-react-native@3.5.0
  

• After these package addition move to ios folder and run pod install.

  cd ios
  pod install
  

You need to upgrade your platform :ios version in your PODFILE

In my case,I changed platform :ios from 10 to 11, and everything worked well

Solved this issue by uninstalling the previous installed Lottie version and then

1- yarn add lottie-react-native@4.0.3
2- yarn add lottie-ios@3.2.3