(SOLVED) notificaiton.fortinet.net not sending emails

Hello
indeed; sometimes  the issue is not related directly with server itself, but with  antispam filter as SPF for example,  certificates validation in the smtp transaction among others

Could you share the output of "show full system email-server" CLI command   in that box?

Hello, I'm getting the following error.. 2 days ago I was able to receive mail without any problems.
Fortigate version 7.2.3

diag debug application alertmail -1

2023-01-22 22:05:55 Arrived msg(type 6, 90 bytes):xxxxxxx
AuthCode: xxxxxxxxxxxxxx
Your authentication token code is xxxxxxxx.

2023-01-22 22:05:55 mail_info:
from:notification.fortinet.net user:xxxxxxxxxxx
2023-01-22 22:05:55 mail_info:
reverse path:xxxxxxx
user name:xxxxx
2023-01-22 22:05:55 to[0]:xxxxxxxxxxxxxxx
2023-01-22 22:05:55 <==_init_mail_info
2023-01-22 22:05:55 create session
2023-01-22 22:05:55 resolve notification.fortinet.net to 1 IP
2023-01-22 22:05:55 ==> send mail
2023-01-22 22:05:55 connecting to 208.91.114.151 port 465
2023-01-22 22:05:55 send mail 0x8f32ad0 session 0x8f610a0
2023-01-22 22:05:59 session_io_event: creating ssl structure for session 0x8f610a0
2023-01-22 22:05:59 create_ssl: 0x7fe7fc8be000
2023-01-22 22:06:00 sessionn 0x8f610a0, SSL connected
2023-01-22 22:06:01 session: 0x8f610a0, rsp_state: greeting, code: 220
2023-01-22 22:06:01 session: 0x8f610a0, rsp_state: ehlo, code: 250
2023-01-22 22:06:01 session: 0x8f610a0, rsp_state: mail, code: 250
2023-01-22 22:06:01 session: 0x8f610a0, rsp_state: rcpt, code: 250
2023-01-22 22:06:02 session: 0x8f610a0, rsp_state: data, code: 354
2023-01-22 22:06:02 === send: Your authentication token code is xxxxxxxx.

2023-01-22 22:06:02 session: 0x8f610a0, rsp_state: data2, code: 250
2023-01-22 22:06:02 session: 0x8f610a0, rsp_state: quit, code: 221
2023-01-22 22:06:02 session finined
2023-01-22 22:06:02 _session_on_destroy
2023-01-22 22:06:02 <== send mail success, m = 0x8f32ad0 s = 0x8f610a0

Hello

Sorry, I cannot see any error in your diag debug output

What about your receiving logs? Do you own your mail server to catch the smtp transaction deeply?

Our e-mail addresses are on office365..notification.fortinet.net says Firewall is being sent, but we do not receive mail.
When I select a gmail email address the mail does not come

Is a pity, those big email players don't provide enough information or logs.

Try to a reply-to address field to attempt to receive more feedback in that address.

config system-email server
   ...
   set reply-to  <mail_address>
end

(I'm trying to get some evidence of antispam filtering of those emails,  SPF , dmarc stuff etc )

Hello there,
TAC suggested to use a different smtp, so I used our O365 account and I solved the problem.