Can't receive email "Connection timed out (Connection timed out)"

Our company is receiving most email just fine. We have a number of companies whose emails to us are failing with errors such as “Connection timed out (Connection timed out)”. Our server is not busy, I am wondering what to check? I have checked DNS settings and everything looks good in mailinabox admin status and also in mxtoolbox. Any advice on where to look for issues? These are Ubuntu servers, the mail server is a separate box from our web server.

Thanks in advance!

Is the dashboard reporting any errors?

Is there a corresponding log entry in /var/log/mail.log?

Hi thanks for the quick reply, there are no corresponding errors in mail.log and the dashboard has no errors.

This initially sounds like a DNS or more likely a firewall issue of some sort, because it sounds like postfix isn’t being called.

That is what I have been thinking, but I am enough of a newbie to not know the DNS well enough to see what could be wrong, and this has all been working up until mid last week.

Speaking of DNS, I lied and there is an issue on the dashboard, I should I fixed it last week but must have made an error. “MTA-STS policy is missing: STSFetchResult.NONE” I added DNS entries for this, could that be the issue?

MTA-STS, frankly, isn’t used by very many servers, so it shouldn’t cause a connection issue. I think the way MTA-STS works is that when you have the message, you don’t have MTA-STS.

MiaB is developed assuming a networking environment identical to a hosted VPS, most importantly where the box has the public IP address directly assigned directly.

Is this how your current networking is configured?

The mailinabox has a public static IP address assigned.

Is it directly on the public Internet or is this through a firewall tool, of some sort?

Directly on the public internet

the domain is if there is anything you can check publicly

It looks like you are using an external DNS for all of your records. The dashboard should have several errors related to this in it.

My guess is that you probably are not wanting to use MiaB as the DNS server for your primary domain. The way around this is to have a second domain that is exclusively for the mail server, then just point the primary domain MX records at the MiaB domain.

The mailinabox is at domain, is that not what you are describing?

I am describing the authoritative name server, which is currently XMission.

For the root domain the MX record is setup as:

|@|MX|**Target:**|Priority: 10

This section of the setup guides describes the configuration (but you would also need to correctly perform the preceding steps).

You can make it work otherwise, but you are fighting against how MiaB is intended to be used, so usually the extra $10 per year is easily justified in reduced admin labor.

What is $10 per year in regards to? We would happily pay this, I probably overlooked or didn’t understand something in the setup.

That would be for an additional domain which you use exclusively for the MiaB server. This way you continue to use the same name server for your primary domain and MiaB with its domain is your email host (similar to when you use Google, Microsoft, etc.).

Ok so you are saying that using a sub-domain is not the preferred way to use a mail server? I guess I thought this was the preferred way to go about this.

To tersely summarize:

Every domain has an authoritative name server.

The authoritative name server hosts the domain DNS records.

MiaB assumes it is the authoritative name server.

You are using XMission as the authoritative name server.

I will also mention I cannot be certain this is the cause of the problem you are currently experiencing, but I also have no way to verify what is causing the problem, as there is nothing in the logs, so it really is up to the senders to determine why they cannot send messages, or you have some other issue you have not posted (e.g., you did not mention the DNSSEC DS record warning that is there, and few others, I’m pretty sure).