Email partially received


I am having issue with one of the mail box, a strange issue.

That particular mail box doesn’t receive all the email. some of them, but not all.
Let s call the problematic email A
If I send an email from test1@domain to A@domain, it works perfectly
If I send an email from to A@domain, it works
If I send email from to A @domain, email not receipt, and 18hr later, I get a message on hotmail saying the message could not be sent
If steam send email for steam guard at A@domain : no email received

why would the mail box receive certain email and not others ?
I don’t see anything in /var/log/mail.log…

any idea where to look ??

Thank you

Could you post the domain name?

Could you share this message perhaps? Without specific information, nobody will be able to assist. Feel free to PM me if so desired.


Sorry about my slow responses time.
Before I stopped receiving certain email, I tried to do the upgrade of mail in a box on my original install with ubuntu 18. wich work, but it was still in version 57 after upgrade

Thinking it was linked to the upgrade, I decided to upgrade to ubuntu 22 and mailiabox 60.1.
Trying to connect to OVH, but not receiving the 2FA, because of this issue, I decided to create a new box at Hetzner (where I moved all my other VPS)

Everything is done : miab 60.1 and ubuntu 22. But I am now waiting for the glue record IP to be updated …
it s been 5 days and it is still not accessible.
I did not anticipate having no email for that long !!! maybe we should write it that it takes a long time for glue record change and dns propagation to happen… I was more expecting 24-72hrs…

Domain is If i check dns propagation for NS, I see it s not yet updated everywhere…

OK… So now my MailInaBox is running on Ubuntu 22 with MIaB 60.1

I have the main domain, that is managed by miab.
my miab is also serving mail for a 2nd domain : (which i use the most)

Now that my glue record is updated,and dns working properly (after I entered the command sudo service nsd restart, it went way faster)

for information
_ DNS for is done by the box
_ DNS for is done by cloudflare.

So i receive most of the email…
after my box went online, I received 20 email from different services I use.
If I send myself an email from a google account, I also receive it
loggin 2fa from binance works

but email I don’t receive are email from an account on and from steam2fa, or from OVH 2FA.

any idea ? could you help see what s going on ?

Doing more testing.
it seems I receive all email coming for de 1st domain :
but in the 2nd domain, administered by cloudfare, I have partial reception.

Any idea on what to do ?

OK I left cloudflare and let MIaB handle all DNS.
All mail came back !
wonder why having cloudflare DNS would block some mail but not others …