Mail merge multiple sessions

[erikfjer]

Mail merge direct to email via SMTP creates multiple sessions for email addresses that the receiver’s ISP “delays”, causing problems. My ISP suggests “slowing down” the emailing, or selecting a mode that prevents “multiple sessions”. I know of no way to “slow down” or “limit sessions”. Here is quoted text from Cox (ISP) “unblock help”
“While reviewing the logs we observed that most of the outbound messages are getting deferred due to below reason: max_session_msgs. To avoid this issue, kindly request you to limit the number of sessions connection.”

Here is the error code received while sending the emails:

• SMTP error from remote mail server after MAIL FROM:<*****> SIZE=5637: 452 4.1.0 <[*****](mail to:*******)> server temporarily unavailable. Refer to Error Codes section at cox.com/residential/support/email-error-codes for more information. AUP#CXMXRT

[Wanderer]

I know no method in LibreOffice as I don’t use mail-merge with email in LibreOffice, but you may also talk to your ISP. We use a dedicated newsletter@ account, wich is the only one to send so many mails we need. But this is a setting on server-side, not LibreOffice.
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Typical newsletter-software like the mail-merge plugin in Thunderbird allows a delay between individual mails.