On the Nylas dashboard, you can view the Auth logs to see any recent errors for your Nylas app. For privacy and security reasons, we don't log the email address or password used in the attempt, as such to find the right entry:

• We recommend either getting a timestamp of the authentication attempt
• Check the auth logs while on a call with a user right after they attempted to authenticate. 

Exchange Errors

Error: EAS is not enabled / Wrong username or password

Connectivity test results: HTTP 403 forbidden response was received

Cause: Incorrect credentials or ActiveSync is not enabled.

Resolution: Confirm credentials are correct.  If they are, try running the Microsoft Connectivity Test (https://support.nylas.com/hc/en-us/articles/4419151406097) for ActiveSync.

• Remove administrator role - admin accounts can not access EAS
• Enable Mobile access via Azure portal > User > Select Account > Mail > Manage mail apps > Enable EAS (this is unticked when becoming admin and not enabled agin when removing the role)
• If the email administrator has disabled Exchange ActiveSync, then this account will not be able to use the Contact scope. Please try re-authenticating again without the contact scope.

Error: ConnectionError(ProtocolError('Connection aborted.', error(104, 'Connection reset by peer')),)

Cause: Our connection to the email server was unexpectedly terminated before we could authenticate.

Resolution: Try again. If it continues to fail, check with email administrator if there are systems in place to block failed authentication attempts and get Nylas's IPs off that list. Also check to see if they have an IP block list or white list.

Nylas IPs can be retrieved by the API endpoint documented here: https://developer.nylas.com/docs/api/#get/a/client_id/ip_addresses

Error: AuthError('No useable credentials',)

Cause: Exchange Web Services rejected the credentials.

Resolution: Confirm credentials are correct.  If they are, try running the Microsoft Connectivity Test (https://support.nylas.com/hc/en-us/articles/4419151406097) for Exchange Web Services and send Nylas Support the results.

If the email administrator has disabled Exchange Web Services, then please contact Support so we can help arrange a solution.

Error: AutodiscoveryError("HTTPSConnectionPool(host='something.com', port=443): Read timed out. (read timeout=10)",)

Cause: The Exchange Autodiscover service did not respond.

Resolution: Nylas uses that service to learn the server host address and full username of the mailbox. The user will need to click on the Advanced Settings when authenticating and fill in the username and server host address. Please contact the email administrator for those values or to get that service running.

Error: AutodiscoveryValidationError('HTTP: Unauthorized',)

Cause: The Exchange Autodiscover service rejected the credentials.

Resolution: Check credentials. If they are correct, the user will need to click on the Advanced Settings when authenticating and fill in the username and server host address. Please contact the email administrator for those values or to get that service running.

Error: Wrong username or password for https://something.com/EWS/Exchange

Cause: The EWS service rejected the credentials.

Resolution: Confirm credentials are correct.  If they are, try running the Microsoft Connectivity Test (https://support.nylas.com/hc/en-us/articles/4419151406097) for Exchange Web Services and send Nylas Support the results.

If the email administrator has disabled Exchange Web Services, then please contact Support so we can help arrange a solution.

Error: Exchange server error, retry later.

Cause: The Exchange server had a transitory error.

Resolution: Retry. Reach out to Nylas support if it continues.

Error: Exchange error 129: The user is configured to allow only some devices to sync. This device is not the allowed device.

Cause: The ActiveSync device is blocked for this user.

Resolution: Check with the email administrator that the ActiveSync device is not blocked for this user (See Checking for Quarantined EAS Devices). Verify the device access rules are set up following our Suggested Office 365 settings guide.

Error: Status 401: Invalid credentials or protocol is not enabled, due to which authentication cannot be completed.

Cause: The Exchange ActiveSync (EAS) protocol is not enabled

Resolution: Run the Microsoft Connectivity Test for ActiveSync.

IMAP errors

Error: LoginError('LOGIN Login error user suspended',)

Cause: Mailbox disabled.

Resolution: Contact email administrator.

Error: Exception(u'Missing required arguments to hash imap account()',)

Cause: Your API call is missing items in the payload.

Resolution:  Review your API call to authenticate the account and ensure all values are present.

Error: ValidationError(LoginError('[AUTHENTICATIONFAILED] Authentication failed.',),)

Cause: IMAP service rejected credentials.

Resolution: Check credentials. Contact email administrator to confirm that this is the correct server host and port number for IMAP.

Error: -2

Cause: Could not reach that server host URL.

Resolution: Confirm with the email administrator what the correct server host and port is for IMAP and SMTP services.

Error: UserRecoverableConfigError('Unable to connect to caldav server. Please check the username is correct, and that you are using an app-specific password. https://support.apple.com/en-us/HT204397',)

Cause: Server rejected the credentials

Resolution: Check credentials and make sure the user is entering an app password instead of their normal password.

Error: <Timeout at ****** seconds=30>

Cause: The connection to the IMAP service timed out.

Resolution: Try again. If still failing, confirm with the email administrator what the correct server host and port is for IMAP and SMTP services.

Error: [ALERT] Please log in via your web browser: https://support.google.com/mail/accounts/answer/78754 (Failure)

Cause: Google interprets the IMAP client as a "less secure application" than the web browser and the user account is not using a 2-Step Verification method. This is an extra security measure from Google when attempting to connect a user account through IMAP.

Resolution: Enable "Allow less secure apps" by visiting https://www.google.com/settings/security/lesssecureapps and retry connecting through IMAP.

Updated November 14, 2023 18:21