This account already exists on your device - Huawei Nova 2S I bought a Huawei Nova 2S while in China.  Installed Google Play Services 14.3.66 (com.google.android.gms_14.3.66_(090408-213742215)-14366030_minAPI26(arm64-v8a,armeabi-v7a)(480dpi)_apkmirror.com).

I then downloaded many google apps (Google, Drive, Music, Gmail, Sheets, Keep, Maps, Hangouts, Youtube) but not all of them.  

** Problem **: After downloading Google Contacts I cannot use the app.  It asks me to sign in and when I attempt to do that I get "This account already exists on your device"

I have now upgraded to (com.google.android.gms_14.5.73_(040408-219655168)-14573021_minAPI23(arm64-v8a,armeabi-v7a)(480dpi)_apkmirror.com) but still no luck.  I am going to post this on Google's contacts support website so will update this if a solution is found.

-I also checked the permissions for Gmail, Play services and Contacts.  I selected "Trust this app" for all three to avoid any possible permission problems.
-Cleared app cache &amp; data for Contacts. Re-started the phone but still no luck.

Some of the resources I've visited:

https://productforums.google.com/forum/#!topic/gmail/GO4l2n3k-1o;context-place=topicsearchin/gmail/This$20account$20already$20exists$20on$20your$20device$20contact - same issue but never solved.

https://productforums.google.com/forum/#!topic/gmail/USU0RXKwNds - again, unsolved

Next update:
Removed google account, was able to sign in to contacts, but once in it didn't sync any data and acted like I never signed in at all with the sign-in button appearing at the top of the menu again.
I FOUND THE ANSWER!!!!

I needed to download Google Contacts Sync, which I got from apkmirror.com.  It asked to manage my google account and access and modify contacts, which is exactly what I wanted.

I really hope this helps those other frustrated people who are experiencing the same problem (perhaps who bought a phone in China :-))