Marketo mails being blocked by receiver's mail server

[Anonymous]

Hi,

We came across a specific customer where all the leads from that customer were marked in marketo as having received our emails but in reality when we check with the customers, none of they seemed to have seen the mail in their inbox despite marketo indicating that the emails were delivered. Upon further checking, none of them are flagged as having opened or clicked the mails in marketo so the mail was probably blocked somewhere along the way.

If we send a direct email to them via outlook, the mails are received successfully by the customers.

Just wondering if anyone has any experience with a similar situation and managed to overcome it?

[John_Clark1]

Hi Serene,

Marketo will only log a Delivered activity for an email if we get a message back from the receiving server saying that it will take the message.  Once that happens we don't have any more control over, or insight into, what happens with the message.  It's possible that it's getting blocked at the server level on their side and never getting to their inbox/spam folder.

In cases like these it's the IT team of the receiving company that needs to look into why Marketo's mails might be getting blocked by there server settings.  Depending on your relationship with them you could also ask them to whitelist Marketo's email sending ip addresses below.

Whitelist Marketo IPs

Add these IP addresses to your corporate whitelist:

199.15.212.0/24

199.15.213.0/24

199.15.214.0/24

199.15.215.0/24

192.28.146.0/24

192.28.147.0/24

94.236.119.0/26

37.188.97.188/32

185.28.196.0/24

103.237.104.0/24

103.237.105.0/24

Some anti-spam systems use the email Return-Path field instead of the IP address for whitelisting. In those cases, the best approach is to whitelist ‘*.mktomail.com’, as Marketo uses several mailbox subdomains. Other anti-spam systems whitelist based on the From address. In these situations, be sure to include all the sending (‘From’) domains that your Marketing group uses to communicate with leads.   

[Anonymous]

Thanks John, I thought as much. Like Sanford Whiteman​ says below, I don't think their IT would do the above just for us...

[SanfordWhiteman]

Serene, some companies detect and immediately delete emails from ESP/MAP services like Marketo.  Thus they are not bounced or "blocked" exactly (because I like to be precise with terminology). Like John says, as far as Marketo knows they are accepted for delivery, but the recipient's mail system simply throws them away.  From a reporting perspective, such messages can't look any different from messages that were delivered all the way to an inbox, then deleted by a human user, since Marketo has no additional information to go on.

Unfortunately, companies that have policies like this in the first place are also unlikely to loosen the policies for you.  I am currently taking extraordinary steps to deal with this situation at one of my clients: we are routing all mail to a particularly troublesome domain through in-house servers, then back out again, so it will take the same path as the person-to-person mail to that same domain, which does go through without fail.  However, you would need to be technically equipped to put such a thing in place.