How long will JetAdvice retry the email with a supply alert or a report?

If the email address is not reachable when the supply alert or report is sent, then JetAdvice will retry for 72 hours.
After that, the supply alert or report will not be sent any more.

If your mail server reject the emails from JetAdvice then this link could be usefull to solve the problem. 
http://community.mxtoolbox.com/blog/550-5-7-1-message-rejected-as-spam-by-content-filtering-intelligent-mail-filtering-with-exchange/