- Plesk for Linux
Cannot send email. The following error appears:
CONFIG_TEXT: Too many concurrent SMTP connections; please try again later
Postfix is used as a mail server.
Remote mail servers restrict SMTP connections due to concurrent connections count limit exceeding.
Note: if you don't have root access to Plesk server via SSH, contact your hosting provider regarding the issue
1. Login to Plesk via SSH
2. Back up Plesk configuration:
# cp /etc/postfix/main.cf /etc/postfix main.cf.bak
3. Add the following parameter to /etc/postfix/main.cf :
# PARALLEL DELIVERY TO THE SAME DESTINATION
smtp_destination_concurrency_limit = 20
4. Apply the configuration change:
# service postfix reload
5. Try to send emails to reproduce the issue. If it still appears, reduce the smtp_destination_concurrency_limit value. If it does not appear, increase the value in order to minimize affecting mail server performance