When i click play online, it says authentication failed.
Can anyone help me?
And it says offline under the PLAY button.

Happened to me as well. Just a relaunch of the game worked for me.

The issue for my Authentication Failure had to do with my localhost address. A cuple of years ago before I began subscribing to Adobe Creative Cloud I had a cracked version of CS5 on my system, it assigned all ip address' that Adobe communicated with to the localhost (127.0.0.1) and save it in the host file located in Windows/system32/drivers/etc. When I removed the software I neglected to correct the host file and as a result my local host address was assigned to 0.0.0.0

To fix it reboot your pc in safe mode and switch your localhost address back to 127.0.0.1. This fixed the issue for me.

Good luck.

The contents of your host file will look something like this:
# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host

# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
127.0.0.1 localhost

I am playing on mac OSX and also can't authenticate. I have even put both the launcher and the game into a list that specially allows all incoming and outcoming connections. I tried to restart the launcher, but still nothing works. Help me please.

wow that localhost thing fixed my connectin problems.... but why would that stop it connecting in the first place?
No other game does....

The only reason I can see it needing localhost is if it's trying to run a server off your machine, that is only supposed to have a local connection... but that doesnt' make sense either. o.O

I have no Idea, but I can't take credit for this, the Game devs had a look at my host file I shared with them and they identified the issue.