Around four days ago, using Manage Engine Service Desk Plus Standard Edition, emails stopped being pulled in to our Helpdesk. No settings had been changed in Manage Engine, and we are using POPS to contact the relevant Exchange Mailbox. On re-entering authentication details and saving, we get the following error message: 

FAILURE: E-mail settings saved successfully. But unable to connect with mail server - Authentication Failed using the the given username and password. 

We have double-checked all the settings, obviously including the username and password,  for POPS

in mailbox configuration and have referred back to Office 365 where no changes appear to have been made. But we are no closer to solving this. We have also restarted the ManageEngine service and restarted the server which hosts it. All to no avail. 

Can anyone advise?

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