Office 365 Email Sync Failed

We have an On Premise Sharepoint 2013 farm where installed a trial version of Helpdesk. We are trying to connect to Office 365 outlook for email. It did not have any error message, We able to receive the test outgoing email. However, we are not able to perform sync.

Following is the email setting

Thanks
Vicky

Hi @Vicky_Tan,

Please reproduce the issue, collect recent SharePoint logs and send them to support@plumsail.com with the link to this community thread.

They are usually located in this folder:
C:\Program files\Common Files\Microsoft Shared\Web Server Extensions\15\LOGS
or in this folder:
C:\Program files\Common Files\Microsoft Shared\Web Server Extensions\16\LOGS

This will help us to understand the issue better.

Sent email. Thank you