Office 365 users recognized as spam

I have the problem that even office 365 users are declared as SPAM on my server, how can I change the SPAM level?

Check in de logs why they are recognized as spam

in which log file should I look for it exactly

when i send emails from GMX Mail, for example, i get the following message

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of
its recipients. This is a permanent error.

The following address failed:

[email protected]:
SMTP error from remote server for RCPT TO command, host: mail.domain.tdl (XX.XX.XX.XX) reason: 550-Rejected because is in a black list at
550 Error: open resolver; DNSBL Error Code - Open/public resolver - The Spamhaus Project


2023-11-20 20:43:22 no host name found for IP address

Exim uses a block list to fight against spam but spamhaus doesn’t allow public resolvers querying their DNS servers so, seems you are using a public resolver like

Options to solve the issue:

1.- I don’t recommended this option. Remove from /etc/exim4/dnsbl.conf and restart exim systemctl restart exim4

2.- Use your own dns resolver or use one that is not blocked by spamhaus.

If you want to test whether your current dns resolver will work, execute this command:

dig (echo '' | awk -F '.' '{print $4"."$3"."$2"."$1""}') +short

If you see nothing, all is good, your dns resolver is not being blocked. If you see an output like then your dns resolver is blocked by spamhaus.

If you want to test whether a resolver will work, add @dns_resolver_ip to the dig command, example using

dig @ (echo '' | awk -F '.' '{print $4"."$3"."$2"."$1""}') +short

3.- If you don’t want to install your own dns resolver or use another public resolver and want to keep your current one, you can request a query key from spamhaus (it is free) and the doc to request and use it is here:

Email and mail server | Hestia Control Panel

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spam problems are solved but roundcube error when replying to the mail was a modsecurty error