(This article is currently in English and Japanese only)
If you see the error message "Unable to Authenticate " and "Failed to Log in" , please check the following four points:
1.You may not be able to sign in on devices that are not Play Protect certified.
If you are unable to sign in on a non-certified device, please consider using a Protect certified devices
https://support.google.com/googleplay/answer/7165974?sjid=5633475268167548578-AP&hl=en
Monster Hunter Now only supports devices that have been certified for Play Protect. For details, please refer to FAQ:Supported Devices.
2.Check your pop-up blocker settings:
We have confirmed that some pop-up blockers block the screen required for Google Login. Please exclude sites related to Google Login from your pop-up blocker settings, or temporarily stop the pop-up blocker settings, and then restart the application and try to log in again. Please contact the service provider of the pop-up blocker you are using for instructions on how to change your pop-up blocker settings or suspend the pop-up blocker.
3. Try Google Play Developer Service /Google Play app Trouble shooting
Please refer to this FAQ.
4. There may be a temporary problem
In addition, you may receive error messages such as "Login failed" or "Authentication failed." if our servers are experiencing a temporary issue or your network connectivity is poor.
Please check your device's network connection and try logging in again after waiting for a while. If the issue persists, try restarting the Monster Hunter Now app.
If the problem still persists, clearing the app cache or reinstalling the app may help resolve the issue. If none of these steps resolve the issue, please contact us for further assistance.