Cloudron Forum

Hi, would it be possible to add Dutch, Japanese and Portugese as well?

@joseph Hi, sorry for the delay in my response. I checked my server according to the examples you gave and got the same results. So that seems to be correct.

What I gathered from this whole conversation (and my subsequent online searches) is that IPv6 is a bit of a problem for email. I guess we have to wait until some conventions are created/adopted.

@girish Thank you!
The initial error seemed indeed to be related to an IPv6 address.

Thanks everyone for helping and answering all my questions.

Hi @joseph I will take a look at your proposed solutions. And see how I can implement that. (And if it works for my usecase.)

@joseph said in not all email received:

So you have to actually check the sending server IP and not your own IP in SpamHaus

When my server checks with Spamhaus on the incoming message (by making a request?) Spamhaus doesn't like it when this is done via a public/open resolver. Resulting in my server bouncing the incoming message.
The error message send to the sender clearly states (after clicking a link) that the problem is with the receiving server not the sending one. Hence my question.

Hi @james ,

Thank you for your reply. Although I am new to Cloudron I did have other servers on the same IP. The reputation is good. Checking on mxtoolbox shows all ok's.

I switched to Cloudron because of a more easy, polished and stable platform (am happy so far ). But I do need to send and receive emails.

I will check the information in the post about spam filtering. Looks interesting.

Still I would like to now the answer, if possible, to my question about what steps to follow when signing up to Spamhaus DQS and making relevant changes to the mail server configuration. What changes would I have to make in Cloudron ?
How to go about ? Or is that a no-go from Cloudron's perspective ?

Hi @james

• IPv6 is enabled and configured correctly
• PTR records are also correctly set

Hi, first time cloudron user here.

Cloudron version: 9.0.10
Ubuntu version: Ubuntu 24.04.3 LTS Linux 6.8.0-87-generic
Vendor: Hetzner VPS

Sometimes I am getting an error that my IP4 is blacklisted on spamhaus. But checking with spamhaus does not confirm my IP is blacklisted. It seems to be the "open resolver" issue.

Some emails sent to me are not delivered but returned with this error message:

Client host [**.**.***.***] blocked using
    zen.spamhaus.org; Error: open resolver;

I read somewhere that this could be related to the Hetzner public DNS. But I do not know how to resolve this.

Spamhaus mentions steps to solve the issue by signing up to their Spamhaus DQS and making relevant changes to the mail server configuration.
It is not clear to me which steps I have to take in regards to the Cloudron setup.

Can someone help me solve this issue? I am not very technical but do have SSH access to my server.