Manually force the Notification Mailer to check for inbound email?

Is there a way to manually force the Notification Mailer to check for inbound email?

We have an issue with the notification mailer connecting to Office 365.  I believe it's a network issue because it is intermittent.  It can connect and process mail just fine sometimes.  So I don't believe it is a configuration issue.  But other times (the majority of times it seems), I see these errors in the log:

Unable to establish a network connection to {outlook.office365.com,993})

But there are also like 10 minute gaps in the log where it does not even try to connect. I'm not sure why this is.  I have the sleep timeouts at the defaults so it should be checking much more frequently, no?