Not receiving mails sent to a G Suite group (list)

Question

my company uses a G Suite account and we have many Gmail users with an own domain (let's say mydomain.com) and many groups (lists) so, if someone sends an e-mail to a group, every user added in that group receives that e-mail.

We actually have 2 servers for monitoring purposes that automatically send some e-mails to 2 of those groups (lists). We were receiving those mails without problems but, since a few days, we noticed we were not receiving them (they were not in the spam folder either). I tried to change the e-mails destination to my G Suite's user account (let's say [email protected]) and I noticed they were being stored then in the spam folder, so I thought maybe Google had changed its spamming policies (why now those mails are being marked as spam and just before we were receiving them?) and maybe that was the reason because the group (list) was not distributing those mails to its users accounts.

I tried to add those servers' IPs in a white list (following this: https://support.google.com/a/answer/60751) but I found there is not a "spam section" in the Gmail's advanced settings!

I don't know what to do but it's very important to us to receive those mails. Some help will be very appreciated. Thanks.

Solution

I know this is an old question but if anybody has this issue again it might help.

If you are not reviving mail then the first place to start is in the Audit logs of the admin console. Under the Email log search, you can see the exact reason why the email was bounced or blocked.

To receive email from an external (not whitelisted) domain go to groups.google.com and under permissions -> post -> check 'Anyone on the web'

To prevent these mails going to directly to the spam folder go to settings -> moderation and uncheck the moderate message settings.