450 too many SMTP connection from…..

[ameno_123]

Hi,
First excuse my bad english, i speak only french,
I have pfsense box(bridge mode, fixed ip) in my networks (40 users)
Sometimes impossibe to send mail from outlook or thunderbird, i have this erreur : 450 too many smtp connection from myip…
Alow with my basic router 3com i dont have this problems.
What is the solution.

Thnks