I cannot understand why the Cocoapod is unable to find the pod specification I created when I run pod install. Could someone help me solve this trouble?
For me it was an issue with finding the spec, not the spec itself. I needed to add a source link to the Podfile, see Podfile documentation
Cocoapods recently added the need to link to the repo that holds the pod spec file you are looking for, the default is:
source 'https://github.com/CocoaPods/Specs.git'
You may need to add multiple source links if you are using more obscure or homemade pods.