Postfix -problems with the number of recipients

NethServer Version: NethServer release 7.3.1611
Module: postfix

mail works correctly sent from Outlook clients.

When I send to a larger contact list, a 0x80070057 error occurs and the mail stays in the Outbox.

if the list is smaller it works correctly.

Is the number of recipients limited by default?

Hi @jose_manuel_Insausti,

I think it’s an Outlook thing, there’s a long list:

Can you reproduce this from different outlook clients?

Could it be that one or some recipients are responsible for the error?

How do you connect Outlook to Nethserver? IMAP?