Unable to Sent Email with Attachment using SMTP Client. Asp.net MVC C# -

i tried send email using smtp client using .net mvc pdf attachment (in memory attachment), not working on live server.

please note: able sent email attachment localhost. when deployed on live server (hosted on iis) not working. same method working without attachment on live server.

i getting following exception:

system.net.mail.smtpexception: failure sending mail. system.net.webexception: remote name not resolved:'smtp.zoho.com' @  system.net.servicepoint.getconnection(pooledstream object owner, boolean async, ipaddress& address, socket& socket& abortsocket6) @ system.net.pooledstream.activate(object boolean async, generalasyncdelegate asynccallback) @  system.net.connectionpool.getconnection(object owningobject, asynccallback, int32 creationtimeout) @  system.net.mail.smtpconnection.getconnection(servicepoint servicepoint) @  system.net.mail.smtptransport.getconnection(servicepoint servicepoint) @  system.net.mail.smtpclient.getconnection() @  system.net.mail.smtpclient.send(mailmessage message) 

here code:

system.io.memorystream ms = new system.io.memorystream(); ms = new memorystream(pdfsharpconvert(rawfilehtml)); system.net.mime.contenttype ct = new  system.net.mime.contenttype(system.net.mime.mediatypenames.application.pdf); system.net.mail.attachment attach = new system.net.mail.attachment(ms, ct); attach.contentdisposition.filename = filename + ".pdf";  var message = new mailmessage(); message.to.add(new mailaddress(recepientemail)); message.attachments.add(attach); message.subject = subject; message.body = body; message.isbodyhtml = true; message.deliverynotificationoptions = deliverynotificationoptions.onfailure; using (var smtp = new smtpclient()) {     smtp.send(message); } issuccess = true; ms.close(); 

here config mail

 <smtp from="myfromemail">  <network      host="smtp.zoho.com"     port="587"     username="myusername"     password="mypassword"     enablessl="true" /> </smtp> 

please how solve problem

thank you.