not able to checkout/ failed to add in my cocopods

[mohsinbmwm3]

[!] Unable to find a specification for XLPagerTabStrip (~> 9.0)

You have either:

• out-of-date source repos which you can update with pod repo update or with pod install --repo-update.
• mistyped the name or version.
• not added the source repo that hosts the Podspec to your Podfile.

Note: as of CocoaPods 1.0, pod repo update does not happen on pod install by default.