"Unable to authenticate" error while trying to create a Pokemon GO account

Solution 1:

There a few reasons why you can be getting this error. Here's some of them, and potential fixes:

According to Niantic (the game makers):

You may receive the “failed to log in” or “unable to authenticate” error message if our servers are experiencing a temporary issue.

If the issue persists, you may close and reopen the Pokémon GO app:

• Android: Touch Settings > Apps > Pokémon GO > Force Stop
• iOS: Double-click the Home button to see your most recently used apps, find the Pokémon GO app, and then swipe up to close the app.

As you've said, you've already checked the servers and they appear to be fine. You've already tried these options above, so there's no point in trying again really, though you can if you want to.

Here are some other things it could be and for you to check:

• You're on an incompatible device. You're using Android 6.0.1 which should work just fine for the game. You need at least 4.4 or up.

• You've been banned. This doesn't really apply to you since this is your first time trying to play.

• You're using a rooted device. Based on the comments on the other answer and your edit, you're aren't. So no need to worry about that.

• The permissions that are set for Pokemon Go on your device are blocking something. It sounds like you've fiddled with this already, but you may want to look into it again. If you have multiple Google Accounts, its possible that the game is using a different one on your phone to log in, causing the error. To fix it, remove all Google Accounts from your device, and put the one you want to use to for Pokemon Go on it only.

• Your devices carrier could be potentially causing the problem. Besides switching carriers, there's not a whole lot you can do to fix this, nor is it really possible to tell if its because of the carrier or not.

(Source)

Here is another potential solution - one I would try after the above:

1. Uninstall the App.
2. Download and install the App from the Play store.
3. Put your phone in airplane mode.
4. Open Pokemon Go. You should see a progress bar of Niantic Labs.
5. Keep your phone in airplane mode until you get to the Google Sign in screen. Once there, a pop up saying that you don't have an internet connection will appear and/or that your GPS signal can't be found. This is because you're in airplane mode.
6. Let that progress bar load all the way. You should be prompted with a login for either Google or the Trainer Club.
7. Use your quick settings to turn airplane mode off (on my phone, I have to swipe down from the top of the screen to access the quick settings).
8. Wait until the connection error message on the top of Pokemon Go screen vanishes.
9. Once the error is gone, attempt to log in via your Google Account.

If this doesn't work, maybe try using a different device (a friends phone perhaps) and see if you can authenticate and play for a bit. If you can't, I think you can at least say that there is something else going on with your account or phone.

Solution 2:

Sometimes the servers have issues, especially when a new version of the game comes out or there is an in-game event. It also is very problematic in the app's code -- not only does it have a messy codebase, it also HATES rooted devices! (reason: if they allow legit players who are rooted, they allow hackers... ... lots and lots of them.... .... who can hop from gym to gym without any need to be near either, etc.)

EDIT: I gave up on the game because I could only play with a "work-around" applied since being rooted.... that eventually stopped working.... and I was playing legit!!!

Solution 3:

Turn off VPN. That’s the problem I had.