Exchange 2010 SP3 RU15, single CAS, 2 DAGs. Receive connector configured to receive internal messages from our voicemail server to relay to the internal users mailbox who received a voicemail. Connector had been working up until about 2 weeks ago.
When attempting to send a message via telnet from the voicemail server I receive a message at the RCPT TO stage stating "450 too many connections from your IP (rate controlled)"
The connector had the MaxInboundConnectionPerSource orignally set at 50, changed to 500, restarted the Transport Services service and the issue still persists.
No recent changes made to the network or the servers. Any ideas where to look next?