I received an email from mailer-daemon saying that my email to a customer's hotmail account hadn't been delivered. I will copy it below without full email addresses. It says that the message will be retried for four days but I would like to know how often it tries or if I can retry myself? Many thanks

----- The following addresses had fatal errors ----- 
[Status: ERROR, Address: < @hotmail.co.uk >, ResponseCode 451, 4.7.500 Server busy. Please try again later from [135.84.80.216]. (AS844) [VE1EUR03FT008.eop-EUR03.prod.protection.outlook.com]] 

Message will be retried for 4 more day(s) 

----- Transcript of session follows ----- 

Received:from mail.zoho.com by mx.zohomail.com 
    with SMTP id 1509369327696882.9527308985499; Mon, 30 Oct 2017 06:15:27 -0700 (PDT) 
Message-ID:<15f6d6c304c.f10 2a2b915807.1639085897474918294@katiejacksilver.co.uk > 
Date:Mon, 30 Oct 2017 13:15:27 +0000 
From:Katie Jack Silver < > 
User-Agent:Zoho Mail 
To:"Jane Jeffery" < @hotmail.co.uk > 
Subject:Re: Website Feedback Form Message www.katiejacksilver.co.uk 
Content-Type:multipart/alternative; 
    boundary="----=_Part_48395_210513629.1509369327695"