Problem getting contacts for emails

I have imported my contacts list from a “VCF” file and after configuring the columns, I execute the importation and a window displayed ’ successfully imported 161 entries’. The contacts are there and visible, but when you try to find them in emails by clicking the “To” button nothing happens. I have checked tie appropriate boxes in settings as suggested in an earlier post but no difference. I have a “Contacts” folder, but no check box. Any ideas???