IOS build not working on Ionic 5

Hello

I am unable to build for the IOS platform due to the following error

diff: /Podfile.lock: No such file or directory
diff: /Manifest.lock: No such file or directory
error: The sandbox is not in sync with the Podfile.lock. Run ‘pod install’ or update your CocoaPods installation.

I am using IOS 5.1.1

Please can you help!

Saeed