Message not responding and not logging in Sierra

Hello,

I need some help with Sierra 10.12.6 not linking properly with Messages.

I checked Date & Time click in and out, make sure App Store and ICloud are logged in. All seem fine. Just IMessages not responding and doesn't allow me to log in.

Could I delete the App and reinstall it individually?

Any tips are appreciated, am working with a Macbook PRO 2012 model.

Thank you in advance

Alberto