felix I'm having an issue too. First off, great job. I'm liking IT Flow and I think it has potential so kudos to you guys! Now, back to my email woes….
I tried setting up the email but it keeps failing. The site is running on an ubuntu server - v22.04 LTS with php 8.1
There are several other vhosts on the server and some relay through a local instance of sendmail. The rest of the vhosts don't.
Sendmail is configured to relay the email to a mail server we have in a protected network. The other websites that don't use sendmail, connect directly to this email server.
I have an account that does work for connecting to this email server for authentication.
Since the web server and email server are completely under our control, we have many options available for different configurations. The email server can accept unencrypted and encrypted SMTP connections but unfortunately, everything I've tried doesn't work.
I've tried using an unencrypted connection as well as encrypted connections - SSL and TLS.
I checked the logs and noticed something. Whether I select no encryption or SSL or TLS, it's always trying to establish an encrypted connection.
This is from the email servers logs:
"TCPIP" 4196 "2023-05-16 03:31:03.232" "TCPConnection - TLS/SSL handshake failed. Session Id: 19, Remote IP: <thewebserver>, Error code: 336151576, Message: tlsv1 alert unknown ca"
I googled that error code, and this was the first result - https://github.com/droe/sslsplit/issues/131
The issue is old but based on what @jakespillstea responded to address his issue, I think the content is relevant.
As I mentioned, even if I select the "None" for the Encryption option in IT Flow, the same error message is logged on the email server.
I'm just trying to setup SMTP, I haven't even got to providing values for the IMAP connection yet.
The Ubuntu server is fully patched. In the php.ini file I had to update the capath for php-curl to work for another website. So the rootca.pem file is as updated as it could be.
My website is also secured with a certificate from Let's Encrypt just like @jakespillstea AND the email server also uses a certificate from Let's Encrypt for TLS and SSL connections.
There are several other sites running on that web server with some of them establishing an SMTP connection to the email server that connect and send email without issue.
Several email clients connect to that email server (publicly) and when I'm in the office even privately. We have this email server, mostly for our customers. It's kind works like an SMTP2GO, or SendGrid service (and you can get a username and password to connect via SMTP to SendGrid.
We don't send millions of emails a day ;-) but it does see it's fair share of load, so I really don't think it's the email server. If it were, I'm sure we would of heard something from some customer by now. But Hey! Anything's possible right!
I glanced over the code a month or two ago but didn't check out the email component.
I was one of those people trying to use MySQL as the backend instead of MariaDB. We have MySQL clusters so why would I want another database engine… Of course, that would be in addition to the MongoDB instances and PostgreSQL instances, and MSSQL instances but whatever.
I don't know if the code has some type of security checking where it's looking at the Common name of the cert and verifying that against the SMTP EHLO or what.
I'll see what else I can figure out later in the week when I have time.
OH, and before I forget, I tried running the last update and the site was updated, but I was left with a database update that needed to be done. Unfortunately, whenever I click on the update button, nothing happens. :-(
But that's another issue for another day.