Problem with sending emails

[RomainB]

Hello everyone,

I'm experiencing an issue with sending emails. Outlook addresses work fine, but when I try to send emails to Gmail addresses, I receive an error message.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

[fasse]

Hmm this sound like Google will block emails from your domain.
Maybe they don't like how you sent the emails. Have you tried to experiment with the mail sent settings. Do you sent the email to roles within 1 email or every user got his own email?

[RomainB]

When I send separate emails to Outlook addresses, the emails go through. However, when I send in a group with both Outlook and Gmail addresses, I only receive the Outlook email and I receive nothing in the Gmail emails

[fasse]

How did you configure the preference Preferences > Email delivery > E-Mail sending mode ?
Is it single or bundled?

[RomainB]

I am in simple mode, but in both cases, there is no sending of emails to Google addresses.

[RVice]

DMARC and SPF related possibly?

I know for a popular CRM, there was a policy change that required "account" access instead of just aliases. Also, GMail aliases for custom domains also need an actual email account (loging/pass) instead of just using forwarding on the server.