Limit smtp_destination_concurrency_limit to a given domain

One ISP (french isp Orange) blocks emails from my server :
Too many connections, slow down. OFR004_104 [104]
I have read some doc about "smtp_destination_concurrency_limit":
/etc/postfix/master.cf:
slow inet n - - - - smtpd

/etc/postfix/transports:
domain1.com slow:
domain2.com slow:

/etc/postfix/main.cf:
slow_destination_concurrency_limit = 10
slow_destination_rate_delay = 40s

But it doesn't work!

How can i do to act over a domain ?