I installed ISPConfig on my new Ubuntu 24.04 server and cannot get Pop3 email working.

Hello, a week ago I installed ISPConfig on my new Ubuntu 24.04 server. I cannot get Pop3 email working on Thunderbird or Outlook 2021. I have SSL successfully installed on all web sites. Here is one of the sites: https://gssfllc.com .

Here are mail log file errors:
2025-04-06T16:01:09.079217+00:00 server2025 postfix/smtp[4891]: warning: DNSSEC validation may be unavailable
2025-04-06T16:01:09.079269+00:00 server2025 postfix/smtp[4891]: warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated
2025-04-06T16:01:09.333962+00:00 server2025 postfix/smtp[4891]: 87E9F6174B: host mta7.am0.yahoodns.net[67.195.204.79] said: 421 4.7.0 [TSS04] Messages from 999.93.996.299 temporarily deferred due to unexpected volume or user complaints - 4.16.55.1; see https://postmaster.yahooinc.com/error-codes (in reply to MAIL FROM command)
2025-04-06T16:01:09.334265+00:00 server2025 postfix/smtp[4891]: 87E9F6174B: lost connection with mta7.am0.yahoodns.net[67.195.204.79] while sending RCPT TO

1) I just purchased this IP address. Is it possible that it was used for SPAM by previous owner?
2) The log file's identification of my server is incomplete. server2025 is not the complete server name.

Thanks for any help!

 

Hi Till,
hostname -f does report correct server name

Tom

 

We were using a gmail and yahoo accounts for testing.

Currently, trying to get any mail client to work. This is from webmail going from name@gssfllc.com to name@gssfllc.com:
server2025 postfix/smtp[12878]: CF10D625D9: to=<name@gssfllc.com>, relay=none, delay=0.18, delays=0.07/0.01/0.1/0, dsn=5.4.6, status=bounced (mail for gssfllc.com loops back to myself)

 

In outlook email account setup I'm getting:
The server you are connected to is using a security ticket that cannot be verified.
The target principal is not correct.
Certificate Information window:
This cert is intended for: All Issuance Policies, All Application Policies
Issued to: server2025.name.com

 

gssfllc.com has an email domain.

2025-04-06T17:22:31.918541+00:00 server2025 postfix/smtp[12878]: warning: DNSSEC validation may be unavailable
2025-04-06T17:22:31.918624+00:00 server2025 postfix/smtp[12878]: warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated
2025-04-06T17:22:31.919049+00:00 server2025 dovecot: imap-login: Login: user=<name@gssfllc.com>, method=PLAIN, rip=::1, lip=::1, mpid=12879, secured, session=<I3FbXR8yWpUAAAAAAAAAAAAAAAAAAAAB>
2025-04-06T17:22:31.928589+00:00 server2025 dovecot: imap(tom@gssfllc.com)<12879><I3FbXR8yWpUAAAAAAAAAAAAAAAAAAAAB>: Disconnected: Logged out in=394 out=713 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
2025-04-06T17:22:32.022322+00:00 server2025 postfix/smtp[12878]: CF10D625D9: to=<name@gssfllc.com>, relay=none, delay=0.18, delays=0.07/0.01/0.1/0, dsn=5.4.6, status=bounced (mail for gssfllc.com loops back to myself)
2025-04-06T17:22:32.025206+00:00 server2025 postfix/cleanup[12876]: 0583362689: message-id=<20250406172232.0583362689@server2025.name.com>
2025-04-06T17:22:32.027039+00:00 server2025 postfix/bounce[12880]: CF10D625D9: sender non-delivery notification: 0583362689
2025-04-06T17:22:32.027099+00:00 server2025 postfix/qmgr[12527]: 0583362689: from=<>, size=3213, nrcpt=1 (queue active)
2025-04-06T17:22:32.028391+00:00 server2025 postfix/qmgr[12527]: CF10D625D9: removed
2025-04-06T17:22:32.145367+00:00 server2025 postfix/smtp[12878]: 0583362689: to=<name@gssfllc.com>, relay=none, delay=0.12, delays=0/0/0.11/0, dsn=5.4.6, status=bounced (mail for gssfllc.com loops back to myself)
2025-04-06T17:22:32.145925+00:00 server2025 postfix/qmgr[12527]: 0583362689: removed
2025-04-06T17:22:32.511866+00:00 server2025 dovecot: imap-login: Login: user=<name@gssfllc.com>, method=PLAIN, rip=::1, lip=::1, mpid=12882, secured, session=<vHtkXR8yXpUAAAAAAAAAAAAAAAAAAAAB>
2025-04-06T17:22:32.524641+00:00 server2025 dovecot: imap(name@gssfllc.com)<12882><vHtkXR8yXpUAAAAAAAAAAAAAAAAAAAAB>: Disconnected: Logged out in=70 out=697 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
2025-04-06T17:22:32.784434+00:00 server2025 dovecot: imap-login: Login: user=<tom@gssfllc.com>, method=PLAIN, rip=::1, lip=::1, mpid=12885, secured, session=<yaRoXR8ybJUAAAAAAAAAAAAAAAAAAAAB>
2025-04-06T17:22:32.790083+00:00 server2025 dovecot: imap(name@gssfllc.com)<12885><yaRoXR8ybJUAAAAAAAAAAAAAAAAAAAAB>: Disconnected: Logged out in=76 out=610 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
2025-04-06T17:22:32.790734+00:00 server2025 dovecot: imap-login: Login: user=<name@gssfllc.com>, method=PLAIN, rip=::1, lip=::1, mpid=12886, secured, session=<0rtoXR8ycJUAAAAAAAAAAAAAAAAAAAAB>

 

This issue is resolved. I had inadvertently setup 'email routing' for this email domain. I in-activated the email routing and my email started working.
Thank you for your timely support!