In my case, the issue was with my Xcode build scheme. When you run react-native run-ios
you may see something like,
info Found Xcode workspace "myproject.xcworkspace"*
info Building (using "xcodebuild -workspace myproject.xcworkspace -configuration Debug -scheme myproject -destination id=xxxxxxxx-xxxxx-xxxxx-xxxx-xxxxxxxxx -derivedDataPath build/myproject")*
In this case, there should be a scheme named myproject in your ios configurations. The way I fixed it is,
Double clicked on myproject.xcworkspace in ios directory (to open workspace with Xcode)
Navigate into Product > Scheme > Manage Schemes...
Created a Scheme appropriately with name myproject (this name is case-sensitive)
Ran
react-native run-ios
in project directory