Issue Troubleshooting Email Delivery Issues in Plesk Obsidian on Ubuntu 22.04

[FreeRoaming]

Server operating system version

Ubuntu 22.04.5 LTS

Plesk version and microupdate number

Obsidian 18.0.65 Update 2

I use Plesk Obsidian 18.0.65 Update 2 on Ubuntu 22.04.5 LTS.

1. I try sending email from a registered domain in plesk to a gmail address. It does not arrive.
2. I try sending email from a gmail address to a registered domain in plesk. It does not arrive.
3. I try registering an email in Thunderbird from a registered domain in plesk. It does not accept the settings displayed in the frontend of plesk /smb/email-address/list/domainId/nr and choose configure mail client.
4. I use Roundcube in plesk to send, message is sent but never arrives at the gmail address. Also no message sent with 2. is received.
5. I use automatic forwarding from plesk to a gmail address, it does not arrive.

Hints/Error messages:
1.

• DKIM Spamprotection is enabled, external DNS is set
• SSL/TLS certificate Let's Encrypt is set

2.

*** MAIL DELIVERY FAILURE REPORT ***

The original message was received at Mon, 09 Dec 2024 07:38:26 -0800 (PST)
from host [redacted).

Subject: redacted
From: [email protected]

Mail delivery to the following recipient has finally failed:

redacted
Last reason: 451 4.4.1
Explanation: Timeout connecting to redacted
Final attempt was: Sat, 14 Dec 2024 16:40:40 +0100 (CET)

Transcript of session:
... while talking to redacted:
>>> CONNECT redacted
<<< 451 4.4.1 Timeout connecting to redacted

3.

ThunderBird failed to find the settings

 

[Martin Dias]

Where do you host the server? Do you have any firewall blocking the mail ports?

 

[FreeRoaming]

Where do you host the server?

On a shared strato server.

Do you have any firewall blocking the mail ports?

How do I figure this out?

 

[FreeRoaming]

Setting the firewall solved sending email from a gmail address to a registered domain in plesk. I also could use Thunderbird.

Receiving mail using gmail does not work.

 

[Martin Dias]

How do I figure this out?

Netzwerk-Firewall im Root Server einstellen | STRATO

Wir erklären Ihnen, wie Sie die externe Netzwerk-Firewall bei Ihrem Root Server Windows und Linux einstellen können.

www.strato.de

check this or ask strato support if there is some firewall blocking port 25, etc

 

[Martin Dias]

Receiving mail using gmail does not work.

Does it go to spam?
Does it work to other providers?

you can also use this to test: Newsletters spam test by mail-tester.com

 

[FreeRoaming]

Now it works for no reason with gmail after having sent an email to mail-tester and having gotten a high score, I sent the same to gmail and it also went through.

 

[FreeRoaming]

Because I got an error message about relay instantly, I thought it was an issue in thunderbird itself on my computer, but it turns out, the signal went around the world to google servers - or wherever they are - and back.