UserAgent: Mozilla/5.0 (X11; Linux armv7l) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.89 Safari/537.36

Steps to reproduce the problem:
1. Raspberry Pi 3b Raspbian up-to-date Kernel and Packages
2. Logging in with your google account to chromium to sync data
3. User-Button
4. Manage Users
5. Add person
6. Pick name and profile photo
7. Hit the Box "manage this user with logged in account"
8. Pick your Account
9. Click Save

What is the expected behavior?
The new user cant be added please check your networkconnection and try again later.

Exact message in german:
"Der neue betreute Nutzer konnte nicht erstellt werden. Bitte überprüfen Sie Ihre Netzwerkverbindung und versuchen Sie es später erneut."

I tried it several times since several days... Started to try on first december 2017

What went wrong?
No user with sync can be added

Did this work before? N/A 

Chrome version: 60.0.3112.89  Channel: stable
OS Version: 
Flash Version: 

All other functions (Especially syncing data) works fine