If you’re facing email delivery problems, you’re not alone. Many server administrators encounter similar issues. Let’s dive into a few common problems and their solutions!

I had a similar issue with ispconfig, I can’t send and receive email after creating an email account on the ispconfig portal. in this post I focus only on sending emails and i will make another post for receiving the email 

I will show you step by step to troubleshoot the issue and find the root cause of your issue.

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This is the mail system at host web1nl.maxtld.com.

I’m sorry to have to inform you that your message could not

be delivered to one or more recipients. It’s attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can

delete your own text from the attached returned message.

                   The mail system

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First of all, you should have three text rules in your DNS provider. 

1. DKIM (DomainKeys Identified Mail)
2. SFP (Sender Policy Framework)
3. DMARC  (Domain-based Message Authentication, Reporting & Conformance)

How to Create these DNS records

SPF:

You can generate spf rule and add to your txt record in your dns controle 

here is an example of spf record 

• v=spf1 a:yourdomainname include:_spf.google.com ip4:yourispconfigIP ~all

to test if the SPF record is working go to mxtoolbox.com add your domain name and continue to check any record you need.

DKIM

To create DKIM record, 

• Go to your ispconfig portal
• Click on DNS – 
• Click on add DNS-Zone
• 
•  domain name – ip will be your ispconfig ip – ns1.yourdoman.com
• click create.