email notification not working in approval by primary owner workflow

Do you use multiple AR servers? If so, please verify (and test!) the Email config from each node. Also, when using EWS mode for delivering emails, you should see mails in the Sent Items of the service account used - is this the case?

Thanks, We only have one single AR server and just use an non Exchange based email system. We provision user account with Exchange online mailbox attributes but not really using it for communication within AR.

I believed the email based approval process requires the Exchange server. All I need right now is the notification sent to the approver and requestor so that they can act on it.

It should work with Exchange Online just fine.  You have to setup your mail settings in Active Roles differently.

Does it means I can't use non-Exchange server for notification? I use the link below to setup the email configuration but was getting the following errors. I know the account works as I tested it on another email client using imap\smtp protocol.

Configure EWS on Active Roles

https://support.oneidentity.com/active-roles/kb/4341143/how-to-configure-office-365-exchange-web-services-as-an-email-provider-in-the-active-roles-mail-configuration

Error using the verify settings within the Email configuration in Active Roles.

Details: The request failed. The underlying connection was closed: An unexpected error occurred on a send. Unable to read data from the transport connection.: An existing connection was forcibly closed by the remote host.

I have the same error. When I'm doing Verify settings it show me Unathorization 401. 
I have configured email but dont work! 

I could never get the AWS working. I just use SMTP for now.