Issue Mail sent via SMTP but not received

[shanmuga]

Server operating system version

Ubuntu 20.04 aarch64

Plesk version and microupdate number

Plesk Obsidian 18.0.47.5

Hi,

My server have Port 25 and Port 465 unblocked.

Mail is successfully sent through SMTP but users not receiving the mail which i sent.

I have also test with this tool : SMTP Test Tool

 

[GwenDragon]

• Had you checked mail queue in Plesk?
• Which provider has the receiver?
• Had you checked if your ser ver is on blocklist?
  For example check:
  

  MultiRBL.valli.org - Blacklist, Whitelist and FCrDNS check tool

  Free multiple DNSBL/RBL lookup and FCrDNS check tool. Test the IP (IPv4 or IPv6) of your mailserver on more than 200 blacklists and whitelists.

  multirbl.valli.org
  BarracudaCentral.org - Technical Insight for Security Pros
  
  
• What is shown in maillog when you send a mail?

 

[shanmuga]

Had you checked mail queue in Plesk?

How to check Mail queue in Plesk

Which provider has the receiver?

I tried Gmail, Yahoo Mail and as well as some temporary email for receiving.

Had you checked if your ser ver is on blocklist?

Blocklist on what?. SMTP ports are unblocked including Port 25

MultiRBL



Baracuda : The IP address 144.XX.39.XX is not currently listed as "poor" on the Barracuda Reputation System.

What is shown in maillog when you send a mail?

Where i can find mail log. even i tried SMTP with external email client like outlook, Thunderbird. it showing mail sent but not received to receiver

 

[shanmuga]

What is shown in maillog when you send a mail?

Mail log : Context – share whatever you see with others in seconds

 

[shanmuga]

I have checked Mail queue in Plesk.

I can see all my mail stucked in queue.

I cleared all queue and send one mail. even it one mail still stucked queue.

 

[GwenDragon]

IPv4 142.250.152.26 and IPv6 [2607:f8b0:4023:c0b::1a] can not be reached.
> Jan 12 06:37:01 nusing-lalande postfix/smtp[3884475]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4023:c0b::1a]:25: Network is unreachable
and others
> Jan 12 06:37:31 nusing-lalande postfix/smtp[3884477]: connect to gmail-smtp-in.l.google.com[142.250.141.26]:25: Connection timed out
and others

Test route for IPs in shell with each command:
traceroute gmail-smtp-in.l.google.com
and post result here

traceroute6 gmail-smtp-in.l.google.com
and post result here

 

[mow]

My server have Port 25 and Port 465 unblocked.

Unblocked where? Your provider might still block port 25 outgoing.

 

[GwenDragon]

@shanmuga Check if you server hoster has a firewall which block outgoing traffic to some ports.

 

[shanmuga]

Unblocked where? Your provider might still block port 25 outgoing.

I have checked with my provider and they says Port 25 is already unblock as per my request last month. I have also added Port 25 in IP table too.

Check if you server hoster has a firewall which block outgoing traffic to some ports.

Yes, they usually block Port 25 by default but they have unblocked now. And my provider says they do not block SMTP by port 465, 587, or 2525.

I also tried to send mail using 465, 587, or 2525 but still getting stucked in Mail Que.

 

[Peter Debik]

@shanmuga You are saying that you cannot connect to GMail, but have you tried connecting so some other email provider instead to verify whether it is a GMail issue or an issue on your server?

Above you are showing a screenshot from MultiRBL that indicates that your server's IP is listed on six blacklists. It can very well be that GMail is blocking your IP(s) altogether. They have their own blacklists. So to make sure that your server is able to send mail through port 25, could you simply try to send an email to another service, e.g your own Hotmail/Outlook, Yahoo or whatever other address?

 

[mow]

@shanmuga You are saying that you cannot connect to GMail, but have you tried connecting so some other email provider instead to verify whether it is a GMail issue or an issue on your server?

They wrote "I tried Gmail, Yahoo Mail and as well as some temporary email for receiving."

I'd recommend trying Newsletters spam test by mail-tester.com.
Also, testing whether any connection to port 25 is possible, e.g. by using `telnet mx00.mail.com 25`, or by using `tcpdump port 25` while using `sendmail -q` or `postqueue -f` to retry the mail queue.

 

[shanmuga]

@shanmuga You are saying that you cannot connect to GMail, but have you tried connecting so some other email provider instead to verify whether it is a GMail issue or an issue on your server?

Above you are showing a screenshot from MultiRBL that indicates that your server's IP is listed on six blacklists. It can very well be that GMail is blocking your IP(s) altogether. They have their own blacklists. So to make sure that your server is able to send mail through port 25, could you simply try to send an email to another service, e.g your own Hotmail/Outlook, Yahoo or whatever other address?

I have never complained that Gmail is not connecting. I said my mails are stuck in Mail queue and it never sending to any services provider whether it a Gmail, Yahoo Mail, Outlook, or a custom receiving server.

I tried all port 25, 465, 587, or 2525 and all failed. I contacted my support hosting provider support team and they mentioned they never block SMTP over 465, 587, or 2525.

 

[shanmuga]

They wrote "I tried Gmail, Yahoo Mail and as well as some temporary email for receiving."

I'd recommend trying Newsletters spam test by mail-tester.com.
Also, testing whether any connection to port 25 is possible, e.g. by using `telnet mx00.mail.com 25`, or by using `tcpdump port 25` while using `sendmail -q` or `postqueue -f` to retry the mail queue.

Even i tried the mail-tester.com which you mentioned. My mail for sent to them to get it tested.