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Authentication Errors

Common authentication issues that users might encounter when connecting accounts to Nylas.

Invalid Credentials

A user receives an invalid password error even if they type the correct password in.

Causes Invalid Credentials

  1. Using an older device.
  2. Autodiscovery could be trying to login to the wrong server.
  3. Missing server settings
  4. Mobile devices aren't provisioned and ActiveSync connections are not allowed.
  5. Nylas devices are quarantined.
  6. Mail server is behind a VPN.

Solution Invalid Credentials

  • Older devices will need to have an app-specific password.
    • If the two-factor authentication service in use doesn't support app passwords, please reach out to support@nylas.com for suggestions.
  • Ask the email administrator what server and the port information should be used to connect. Then, try logging in again by adding the settings under advanced settings.
  • Make sure mobile device provisioning is enabled and that ActiveSync connections are allowed: see Suggested Office 365 Settings.
  • Check that Nylas devices aren't quarantined or blocked: see Checking for quarantined EAS devices.
  • If a user's mail server is behind a VPN or firewall or has strict MDM policies in place, we may not be able to support connecting their account.

You might have an invalid credentials error for Microsoft users that is not related to a password change or expiration. Microsoft identity platform lets administrators set token access.

When a token expires, Nylas needs a new token to connect to the email server. You can review the expiration dates for tokens in Configurable token lifetimes in the Microsoft identity platform.

Temporary Mail Server Error

The mail server experienced a temporary error.

Causes Temporary Mail Server Error

  • Connection blocked due to excessive usage
  • Login failed due to an unknown mail server error
  • Account is disabled
  • Network connection issues
  • Too many simultaneous connections
  • Temporary authentication failure

Solution Temporary Mail Server Error

  • Retry the request
  • Reach out to the mail provider for more information

Exchange Autodiscovery Failed

Nylas was unable to determine the correct connection settings using Autodiscovery automatically.

Solution Autodiscovery Failed

  • The user should reach out to their mail administrator and ask for the correct connection settings so they can manually connect.

  • If a user's mail server is behind a VPN or firewall or has strict MDM policies in place, we may not be able to support connecting their account.

Connection Error

Nylas was unable to connect using the server settings that were provided.

Solution Connection Error

  • The user should reach out to their mail administrator and ask for the correct connection settings so they can manually connect.
  • Test your Exchange Autodiscovery
  • If a user's mail server is behind a VPN or firewall or has strict MDM policies in place, we may not be able to support connecting their account.

Office 365 Refresh Token

When authenticating with Nylas using Office365 OAuth, users may sometimes receive the following error after authentication:

Error while trying to fetch an OAuth token

You will notice in the callback url at the top of the browser has M.R3_BAY... or M.R2_BAY referenced in it.

The end-user is trying to authenticate one of these accounts:

  • Office 365 family
  • Office 365 personal
  • Office 365 free
  • They are with a private group

Azure AD does not support these account types, and OAuth will fail.

Solution Office 365 Refresh Token

Use Basic Authentication instead of Modern/Oauth. If using Hosted Authentication you can fool the Authentication workflow into basic by typing in nonsensical email i.e. gobbly@wobblyjumper.no into the login_hint (email) prompt, you will then be provided with all the provider options.

Office 365 OAuth 403 error

  • Status 403

When authenticating with Nylas using Office365 OAuth, users may sometimes receive the following error after authentication:

Status 403: Office 365 returned us an email address different from the one that started the authentication process.

Solution Office 365 403

  • When using OAuth, the email address used to authenticate must remain the same throughout the process.
  • Ensure the user is not entering or selecting a different email address on Office 365 than originally entered on Nylas.
  • Make sure the user is not attempting to log into an alias. They must authenticate with the main account.
  • If the issue persists, ask the user to log out of all Office365 accounts and then try again.
    Alternatively, ask the user to try authenticating from an Incognito or Private browser session.

IMAP Support Disabled

  • Nylas uses IMAP and SMTP to sync and send mail, so if IMAP is not enabled on the mail server we can't support it.

Server does not support SSL

  • We require secure connections to the mail server to sync and send mail. The user's mail server must either have SSL/TLS enabled, or have the capability to upgrade to a secure connection using STARTTLS.

Incorrect connection settings

  • The server and port settings are incorrect. The user should reach out to their mail provider to find the correct connection settings.