A bounce message that says "Remote Server returned: '602 Attempted to send the message to the following IPs:'", is a generic message indicating a failure to connect to a recipient's mail server. Several factors can cause this issue. To determine the exact problem, you will need to review the Delivery Logs.
- Log in as a system administrator.
- Click on Manage, then Troubleshooting.
- Click on the View Logs tab.
- Set Type = Delivery, Search = "Reason: Remote host said: 602", and Filter = Display Related Traffic.
- Then click the Search button.
In this example, we find "Timeout connecting to 74.125.24.27 (Id: 1)" in the logs
[2025.04.16] 16:52:24.587 [11399151] [RemoteDeliveryQueue] Begin Processing.
[2025.04.16] 16:52:24.587 [11399151] Sending remote mail from USER@DOMAIN.TLD
[2025.04.16] 16:52:24.587 [11399151] MXRecord count: '5' for domain 'gmail.com'
[2025.04.16] 16:52:24.587 [11399151] Attempting MXRecord Host Name: 'gmail-smtp-in.l.google.com', preference '5', Ip Count: '1'
[2025.04.16] 16:52:24.587 [11399151] Attempting to send to MXRecord 'gmail-smtp-in.l.google.com' ip: '74.125.24.27'
[2025.04.16] 16:52:24.587 [11399151] Sending remote mail to: USER@gmail.com
[2025.04.16] 16:52:24.587 [11399151] Initiating connection to 74.125.24.27
[2025.04.16] 16:52:24.587 [11399151] Connecting to 74.125.24.27:25 (Id: 1)
[2025.04.16] 16:52:44.598 [11399151] Timeout connecting to 74.125.24.27 (Id: 1)
Here are some steps that can be used to try and track down the issue.
NOTE: All tests are to be run on the local SmarterMail server for proper results.
The first step is to test that IP and PORT from your server to see if you receive an error or a 220 (good) response (STEP #1). If this connects as expected, please try to resend the failed email, as the issue might have resolved itself. If you do not receive a 220 response, proceed to STEP #2 to check whether you can connect at all. If you can access google.com, we will need to see if the IP itself is reachable by following STEP #3. (NOTE: This may fail if ping is disabled for this IP.)
From here, it will depend on your environment. The purpose of the tests is to check the network directly by excluding SmarterMail from the equation. The following steps can be used to check routing and firewalls, but much of this will depend on your network setup.
- Network connection test to the IP PORT
- CMD Prompt
telnet 74.125.24.27 25 - PowerShell
Test-NetConnection -ComputerName 74.125.24.27 -Port 25 -InformationLevel Detailed - Linux/MacOS
nc -vz 74.125.24.27 25
- If this fails, do a test on a public site to see how widespread the issue is ( google.com:80 )
- CMD Prompt
telnet google.com 80 - PowerShell
Test-NetConnection -ComputerName google.com -Port 80 -InformationLevel Detailed - Linux/MacOS
nc -vz google.com 80
- Is the IP reachable from your server
- ping 74.125.24.27
- See the path the connection takes leaving your server (First few hops will be your network)
- Windows
tracert 74.125.24.27 - Linux/MacOS
traceroute 74.125.24.27
- Disable Windows Firewall for testing [wf.msc (Windows Defender Firewall with Advanced Security)]
NOTE: You may lock yourself out. Only do this if you have console access or out-of-band management available.- PowerShell
Set-NetFirewallProfile -Profile Domain,Private,Public -Enabled False - Re-enable all once done
Set-NetFirewallProfile -Profile Domain,Private,Public -Enabled True - Show current settings
Get-NetFirewallProfile
- Routing details
- CMD ( limited testing potential )
route print - Powershell
- # Full route table
Get-NetRoute
# Route to specific IP
Get-NetRoute -DestinationPrefix 74.125.24.27/32
# Default route (used if no more specific match)
Get-NetRoute | Where-Object { $_.DestinationPrefix -eq "0.0.0.0/0" }
# Interface info
Get-NetIPConfiguration
# EXAMPLE OUTPUT: (NOTE: ifIndex = InterfaceIndex, so yes, they are using the correct interface in this example)
#
# PS C:\Windows\system32> Get-NetRoute | Where-Object { $_.DestinationPrefix -eq "0.0.0.0/0" } | ft -AutoSize
#
# ifIndex DestinationPrefix NextHop RouteMetric ifMetric PolicyStore
# ------- ----------------- ------- ----------- -------- -----------
# 5 0.0.0.0/0 10.1.5.1 0 25 ActiveStore
#
# PS C:\Windows\system32> Get-NetIPConfiguration
#
# InterfaceAlias : Ethernet 2
# InterfaceIndex : 5
# InterfaceDescription : Intel(R) 82574L Gigabit Network Connection
# NetProfile.Name : st.local
# IPv4Address : 10.1.5.65
# IPv4DefaultGateway : 10.1.5.1
# DNSServer : 10.1.10.16
# 10.1.9.8
Linux/MacOS
ip route
ip route get 74.125.24.27
# EXAMPLE OUTPUT:
#
# [SSH]tony [host]sup-ascholzl | ~ | :) | > ip route
# default via 10.1.5.1 dev ens18 proto dhcp src 10.1.5.37 metric 100
# 10.1.5.0/24 dev ens18 proto kernel scope link src 10.1.5.37 metric 100
# 10.1.5.1 dev ens18 proto dhcp scope link src 10.1.5.37 metric 100
# 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
# 172.19.0.0/16 dev br-8899af4a0a0c proto kernel scope link src 172.19.0.1 linkdown
#
# [SSH]tony [host]sup-ascholzl | ~ | :) | > ip route get 74.125.24.27
# 74.125.24.27 via 10.1.5.1 dev ens18 src 10.1.5.37 uid 1000
# cache
Other errors that you may see that can trigger 602 bounce
- Remote Server returned: '602 Failed to connect to the recipient's mail server. No MX records were found for the 'DOMAIN.TLD' domain. Status: 544 5.4.4 Host not found (not in DNS).Attempted to send the message to the following IPs: 1.1.1.1'
- [2025.03.14] 08:00:14.921 [50614713] Connection to 150.136.189.171:25 from {IP_ADDRESS}:60522 succeeded (Id: 1)
[2025.01.23] 16:35:57.149 [69061047] WARNING: Certificate name mismatch. Expected Hostname: mx.opusnet.com, Certificate Information: Subject=CN=mx01-hio01-opus.opusnet.com Issuer=CN=R10, O=Let's Encrypt, C=US
[2025.01.23] 16:35:57.149 [69061047] Attempt to ip, '205.235.95.120' success: 'False'