We have two Edge servers deployed at our Central location where it accepts mails from all other site and send it to Internet and vice versa. There is no problem for outgoing mails but while receiving the mails from the internet there is always an average queue of 600 to 700 mails (some time goes up to 2000). After analysing the issue we found the below errors..
- LED=451 4.7.0 Temporary server error. Please try again later. PRX6
- 451 4.4.0 SMTPSEND.SuspiciousRemoteServerError; remote server disconnected abruptly; retry will be delayed
- 421 4.4.2 Connection dropped due to TimedOut
We have then picked random 10/12 recipients from the error queue and found all of ‘em were from a specific site.
we have tried the below solution... after searching for resolution on the Internet
- Tried enabling protocol logging but nothing found
- Since it was more likely to be a DNS issue, tried manually adding DNS server IPs in the ‘Default front end receive connector’ properties.
- Tried adding DNS server IPs manually into both Transport servers in ‘DNS Lookup’ setting in the server properties.
- Tried adding local server's IP to the hosts file.
- Checked if SMTP fixup is enabled on Firewall.
- Verified the receive connector security settings.
- Verified the CPU and Memory utilization is normal.
- Disabled the Performance Counter on both Transport Server to ensure memory usage.
but nothing seems helping
now the problem is because of this there is a mail delay of at least 20 minutes for incoming mails.
Need help resolving the same.
Neilesh