If an app can’t import vCards into Contacts on Mac
Contacts exports contact information as vCard 3.0 files, but some apps don’t accept files in this format. If an app can’t import vCards you exported, try changing the vCard file format, then exporting the vCards again.
In the Contacts app on your Mac, choose Contacts > Settings, then click vCard.
Select the 2.1 vCard format.
Export the contacts again; change the encoding as necessary.
Be sure to select the 3.0 vCard format again when you’re done.