Many players have reported multiple login glitches. The most common problem I have personally met with is the "GPS not found" glitch. It sometimes happens if one forgets to engage tracking before starting up the app. But, what about the "Unable to Authenticate" error? And how can it be fixed?
This is the screen that welcomes most players using Niantic Labs' "Trainer Club" part of the app. After seeing this message, many players carried the fear that they may have done something wrong, and were banned as a result.
The most common reason this message appears is not as a result of being banned, but from server overload. Although this is the likeliest reason for notification, it is not always the reason. I'm sure some people have seen this message as a ban, but don't worry if you are walking around and playing it on your phone.
Internet Reaction to Authentication Error
Some players have reported losing entire inventories of Pokemon as a result of this error on start-up. Most player account regarding having to start over seemed to be directing more towards those who signed up through the Pokemon Trainer Club. Very few players using a Google Play account have reported having to restart their entire game.
One solution presented online suggested the following steps to solve this problem:
1. Clear recent apps to shut down Pokemon Go completely
2. Go to settings and turn on airplane mode
3. Start the app again, and you should receive the "no internet connectivity" message
4. Turn off airplane mode and go back to the app and login again.
Some users reported positive results with this method. But, if this did not work, server overload is the likeliest issue for the repeated showing of the message. You can check the status of the server you are connected to by clicking on the link below.
The link here will show you how many reports have come in about server and authentication issues and how many were resolved:
I hope this guide helped out if you were having similar issues starting up Pokemon Go. Did trying out these steps help you? Any other issues that weren't addressed in the article? Let us know in the comments and we'll see how we can help!