Project 'Pods' was rejected as an implicit dependency for 'Pods.framework' because its architectures didn't contain all required architectures

Possible Solution:

1. Open Xcode project (cocoapods project) using .xc... file.
2. Select Pods project in the project navigator (blue icon on left).
3. Under Project, ensure Pods (blue icon) is selected.
4. Navigate to Build Settings.
5. Set Build Active Architectures Only = No (for both debug & release).
6. Optional: set base sdk to latest iOS (or select the preferred platform/version).

Note: This solution resolved this issue (warning and linker error) for me.

Suggested resources:

Github Project: https://github.com/CocoaPods/CocoaPods/issues/2053 Github Pull Request: https://github.com/CocoaPods/CocoaPods/pull/1352

For future Googlers: Also make sure that your podfile targets the same iOS version your project targets:

For example, if you're targeting iOS 10.0 in your Xcode project your podfile should include platform :ios, '10.0' at the top, too.

On a very new project on Xcode 9.4.1, the issue was that my Podfile's deployment target was set to platform :ios, '11.0' while my project's iOS deployment target was set to 10.3.

This caused the generated Pods project to target iOS 11.0 (supported by only 64-bit devices on arm64 architecture), but since my main project targets 10.3 and includes armv7 devices, this doesn't work when archiving a Release build since a Release build also builds nonactive architectures by nature (unless you only support iOS 11 devices).

The fix then is to simply change the Podfile's deployment target to match your main project's, in my case it's platform :ios, '10.3'. Afterwards, run pod update and the Pods project should be regenerated. Launch Xcode, perform a clean and you should be able to run the archive process.