Cocoapods: Unable to find a specification for `Firebase/Core`

Question

I have this in podfile:

pod \'Firebase/Core\'
pod \'Firebase/Messaging\'

but getting this error:

[!] Unable to find

Answer 1

try to delete the file podfile.lock
it helps with issue:

[!] CocoaPods could not find compatible versions for pod "Firebase/Core":
In snapshot (Podfile.lock):
Firebase/Core (= 4.8.1)