Exim routing to smarthost for inbound mail

[mr-route43]

Hello!
I'm having some trouble with a new server we are setting up and I can't wrap my head around it. I'm comparing the configuration to another server that is working and has the same cpanel version, and I can't find what's wrong.

Basically, I set up a smarthost and I can send emails just fine. But incoming mail are somehow routed to the smarthost even if the configuration should route them internally.

What I did to have a clean test was to backup my exim config, reset it to defaults and only change AUTH, ROUTERSTART and TRANSPORTSTART sections, with standard conf:

smtp_login:
driver = plaintext
public_name = LOGIN
client_send = : USERNAME : PASSWORD

send_via_smtp:
driver = manualroute
domains = ! +local_domains
transport = smtp_smtp
route_list = * <smarthost>
host_find_failed = defer
no_more

smtp_smtp:
driver = smtp
port = 2525
hosts = <smarthost>
hosts_require_auth = <; $host_address

However if I send an email to a test domain I setup, I see that exim tries to route it externallly:

Event: failure error
Sender User: -remote-
Sender Domain:
From Address: [email protected]
Sender:
Sent Time: Dec 13, 2022, 3:22:15 PM
Sender Host: mail-he1eur04on2052.outbound.protection.outlook.com
Sender IP: 40.107.7.52
Authentication: localdelivery
Spam Score: 1.9
Recipient: [email protected]
Delivered To:
Delivery User: -system-
Delivery Domain:
Router: send_via_smtp
Transport: smtp_smtp
Out Time: Dec 13, 2022, 3:22:15 PM
ID: 1p56Aw-0001f5-GO
Delivery Host: mail.smtp.com
Delivery IP: xx.xx.xx.xx
Size: 10.79 KB
Result: TLS_AES_256_GCM_SHA384:256 CV=yes: SMTP error from remote mail server after end of data: 550-From header sender domain not verified (office365domain.com)\n550-On your Settings > Sender Domains page\n550 verify the sender domain or email to be allowed to send.

I have tried the steps in https://support.cpanel.net/hc/en-us/articles/4402368750871-Can-t-receive-emails-in-my-cPanel-server-
especially checked that the test domain is present in localdomains file. Also, checked global mx records. And since I see the email on my cpanel, I assume all of the ports are working.

Could you please give me a hand in troubleshooting this? I feel like it's something real simple but I can't se it.

Running CloudLinux v8.6.0 with cPanel 106.0.11 on a Google cloud engine VM.

Thanks a lot!

 

[cPRex]

Hey there! You mentioned the domain is in the localdomains file - is it also set to localdomains inside the cPanel >> Email Routing interface?

 

[mr-route43]

Hello!
Thanks, I checked and it was set to automatic. I set it to localdomains:

email routing

Unfortunately, still got the same issue

edit to add a bit more info:
I have compared the exim.conf file with the other server. Aside for the different smarthost we are testing, everything is exactly the same.

 

[cPRex]

Well that's just odd - can you create a ticket with our team so we can check it out?

 

[mr-route43]

Thank you,
I managed to get it working with support.

I was using the default mail account of a test customer, and I'm guessing there was some issue with the hostname (on google cloud)that was messing up routing. After I fixed the hostname for good and created a new email account, everything is working great.