Cannot open a connection to the mailserver smtp.sendgrid.net:587 -- Operation now in

[haivcci]

Hi all expert Bros,

I have two VPS(s), one is running Debian 11 with Hesiacp (Nginx) and another is Ubuntu 22.04 is running OpenLiteSpeed (CyberPanel).

I installed Monit for both to monitor my VPS(s). With the same configuration but it's only working on Debian 11 (I received alert emails).

It didn't work on Ubuntu 22.04. The errors from the Monit log below:



[2023-05-09T14:47:45+0000] error : Mail: Delivery failed -- no mail server is available
[2023-05-09T14:47:45+0000] info : Adding event to the queue file /var/lib/monit/events/1683643665_55e9fe7cd6f0 for later delivery
[2023-05-09T14:48:45+0000] error : Cannot connect to [smtp.sendgrid.net]:587 -- Connection timed out
[2023-05-09T14:48:45+0000] error : Cannot open a connection to the mailserver smtp.sendgrid.net:587 -- Operation now in progress
[2023-05-09T14:48:45+0000] error : Mail: Delivery failed -- no mail server is available
[2023-05-09T14:48:45+0000] error : Alert handler failed, retry scheduled for next cycle
[2023-05-09T14:51:45+0000] error : Cannot connect to [smtp.sendgrid.net]:587 -- Connection timed out
[2023-05-09T14:51:45+0000] error : Cannot open a connection to the mailserver smtp.sendgrid.net:587 -- Operation now in progress
[2023-05-09T14:51:45+0000] error : Mail: Delivery failed -- no mail server is available
[2023-05-09T14:51:45+0000] error : Alert handler failed, retry scheduled for next cycle



The mail settings for Monit that working well on Debian 11 are below:



#Mail settings


set mail-format {
from: info@ (info@fiverservices.com)example.com
subject: MAXKVM Server - monit alert -- $EVENT $SERVICE
message: $EVENT Service $SERVICE
Date: $DATE
Action: $ACTION
Host: $HOST
Description: $DESCRIPTION


Your faithful employee,
Monit }
set mailserver smtp.sendgrid.net port 587
username "apikey" password "SG.uUX2-I1jQdO1p78bic2Jcw.v6zq2ztsrasfddfsdxjabwc-HU0_VLO5aeTsFz8JliXXXX"
using TLS with timeout 30 seconds
set alert exampleemail@gmail.com #email address which will receive monit alerts


Could you please give me a hint?

I don't know why it Cannot connect to [smtp.sendgrid.net]:587 -- Connection timed out

port is not block, I even disabled CSF firewall but still the problem.

Thanks