Unable to enable Google Two-factor Auth - Joomla! Forum - community, help and support

hi all,

i have fresh install of joomla 3.6.4 , cannot two-factor auth work @ all. scan qr code, enter code , there no button "select" - says: "please enter security code displayed in google authenticator in field below , select button"

but button? i've tried clicking save, i've looked on page! code correct, i've tried spaces, without spaces - everything.

mcrypt installed , working.

system info:

code: select all

linux kernel         4.4.0-45-generic
database version         5.5.5-10.1.18-mariadb-1~xenial
database collation         utf8_general_ci
database connection         collation   utf8mb4_general_ci
php version            7.0.8-0ubuntu0.16.04.3
web server            nginx/1.11.5
webserver php interface   fpm-fcgi
joomla! version         joomla! 3.6.4 stable [ noether ] 21-october-2016 16:33 gmt
joomla! platform version      joomla platform 13.1.0 stable [ curiosity ] 24-apr-2013 00:00 gmt
user agent            mozilla/5.0 (windows nt 6.1; win64; x64) applewebkit/537.36 (khtml, gecko) chrome/55.0.2883.35 safari/537.36

php info:

code: select all

mcrypt support   enabled
mcrypt_filter support   enabled
version            2.5.8

select button reference google authenticator app on phone. if have updated version of app, not see button guess know how security code.

try of these. before initiating, delete entry phone app , scan fresh qr code each of following steps:
1) extensions -> plugins , disable both 2 factor authentication - yubikey , 2 factor authentication - google authenticator. logout , login again , enable google plugin.
2) missing mcrypt on server or not configured properly.
3) check timezone joomla (in global config, server) , of server. , if find issue, change timezone , scan qr code again. existing key not work.