Yu Yuphoria contacts not appearing

Though specific solutions to this issue do not seem to be available, yet I would advice you to clear cache of the dialler app. To do this, go to your Application Manager , goto All Apps and then locate Phone App. The name may differ on your CM OS - I am going by the standard Android menu. Tap on the Phone app and clear the cache. This should ideally solve your problem.

This is the problem with the application dialer of your phone. In Android phone, some applications require different other applications and files to run smoothly. The problem might have occurred because the files used by application dialer are corrupted due to virus or any other issues.

You can try clearing data of the app dialer or phone from application manager. If this does not work, backup important data from your phone and restore it to factory setting. This should work.