Solved

Intermittent 5.5.0;550

Posted on 2014-02-11
3
144 Views
Last Modified: 2014-04-28
Hey everyone,

I'm having a little trouble narrowing down the cause of an intermittent mail flow issue for a client.

A few times a week, an external user receives a bounce-back from my clients mail server, here is the important information from the bounce-back message:

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.

<mail.remote.com #5.5.0 smtp;550-(mail.remote.com) [98.X.X.X]:1939 is currently not permitted>


Obviously the client's actual domain is not "remote.com", this is merely a placeholder. Also, while the mail may get rejected randomly, waiting a few minutes and re-sending appears to work for the time being.

Pertinent information about my client:

1. My client's internet connection is currently under fairly heavy load, which does increase their MX server's response time. An upgrade is already being looked at for the connection, we're waiting on the ISP.

2. I have received no other complaints from my client regarding external e-mails that are getting rejected or not coming through.

3. My client uses MXLogic, however, I have verified via a mail audit and a phone call with their support that these e-mails are not getting rejected by them. In fact just to be safe, I've added a *@domain wildcard and a specific entry for the user (redundant, I know).

Pertinent information about the remote sender:

1. I setup a PRTG probe to monitor SMTP traffic on their MX server, it can spike up to 1800ms response time at certain times throughout the day (usually 0830-0900) and is averaging out at 300ms. However, I was not able to match up any bounce-backs to any spikes on their mail server.

2. I called the remote sender's IT company and they did not report any issues.

My Current Theory:

Due to the stress of my client's connection and the stress of the remote sender's server, perhaps this is just too much delay and is causing a timeout.

If you need any more information from me, please let me know, thanks!
0
Comment
Question by:menreeq
  • 2
3 Comments
 
LVL 31

Accepted Solution

by:
Gareth Gudger earned 500 total points
ID: 39852165
Have tracking logs at MXLogic confirmed this message was delivered to your server?

If you use the Message Tracking Logs in Exchange, do they reflect the same error? 550.x.x

Perhaps even check the SMTP Protocol / Connection logs, if you know what time the original message was sent, to see if it was rejected there.
0
 

Author Closing Comment

by:menreeq
ID: 40027645
issue turned out to be on the sending servers end.  Their IT department did not share what the issue they found was.
0
 
LVL 31

Expert Comment

by:Gareth Gudger
ID: 40027712
Glad you got it resolved.
0

Featured Post

Optimizing Cloud Backup for Low Bandwidth

With cloud storage prices going down a growing number of SMBs start to use it for backup storage. Unfortunately, business data volume rarely fits the average Internet speed. This article provides an overview of main Internet speed challenges and reveals backup best practices.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article lists the top 5 free OST to PST Converter Tools. These tools save a lot of time for users when they want to convert OST to PST after their exchange server is no longer available or some other critical issue with exchange server or impor…
How to resolve IMCEAEX NDRs in Exchange or Exchange Online related to invalid X500 addresses.
In this video we show how to create an Address List in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Organization >> Ad…
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…

839 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question