Error
Error Code:
1029
SAP S/4HANA Error 1029: Communication Connection Failure
Description
Error 1029, ERR_COM_CONNECT, indicates a failure in establishing a communication connection from SAP S/4HANA to an external system, service, or database. This typically occurs during data integration, remote function calls, or when accessing resources outside the core S/4HANA instance.
Error Message
ERR_COM_CONNECT
Known Causes
4 known causesNetwork Connectivity Issues
The network path between SAP S/4HANA and the target system is experiencing outages, packet loss, or general instability preventing successful communication.
Misconfigured Connection Settings
Connection parameters within SAP S/4HANA (e.g., RFC destinations, system aliases, hostnames, port numbers) are incorrect or outdated, leading to connection attempts to the wrong location.
Target System Unavailability
The external system, database, or service that SAP S/4HANA is attempting to connect to is currently offline, shut down, or otherwise unreachable.
Firewall or Security Blocks
A firewall (network or host-based) or other security measures are actively blocking the necessary communication ports or protocols between SAP S/4HANA and the target system.
Solutions
4 solutions available1. Verify Network Connectivity and Firewall Rules medium
Ensures that the SAP S/4HANA system can reach its intended communication endpoints by checking network paths and firewall configurations.
1
Identify the source and destination systems involved in the communication failure. This could be the SAP application server, the database server, or an external system.
2
On the source system, test basic network connectivity to the destination system using `ping` and `telnet` (or `nc` on Linux). Ensure the relevant ports are open.
ping <destination_ip_or_hostname>
telnet <destination_ip_or_hostname> <port>3
On the destination system, verify that the SAP S/4HANA instance or the relevant service is running and listening on the expected port.
netstat -tulnp | grep <port>4
Consult with your network administrators to review firewall rules on both the source and destination sides, as well as any intermediate network devices. Ensure that traffic is allowed between the SAP S/4HANA components and any external systems on the required ports.
5
If using cloud environments (AWS, Azure, GCP), check security group or network security group rules to ensure open communication channels.
2. Check SAP Gateway Configuration and Status medium
Validates the SAP Gateway service, which is crucial for RFC and other communication protocols used by S/4HANA.
1
Log in to your SAP S/4HANA system using SAP GUI.
2
Execute transaction code `SMGW` (Gateway Monitor).
SMGW3
In the `SMGW` transaction, check the 'Gateway Status' section. Ensure the gateway is running and no critical errors are reported.
4
Navigate to 'Goto' -> 'Expert Functions' -> 'Display Entries' to check registered programs. Ensure that the expected programs are registered.
5
If the gateway is not running, attempt to start it using transaction `SMGW` -> 'Goto' -> 'System' -> 'Start Gateway'. If this fails, investigate the operating system logs on the application server for gateway-related errors.
6
Verify the `gw/acl_mode` parameter in `RZ10` (or `RZ11`) and ensure it's configured correctly to allow necessary connections. Refer to SAP Notes for recommended settings.
3. Review Database Listener Status and Configuration medium
Ensures that the underlying database listener is active and correctly configured to accept connections from the SAP S/4HANA application servers.
1
Identify the database system (e.g., SAP HANA, Oracle, SQL Server) used by your SAP S/4HANA system.
2
For SAP HANA, log in to the HANA Studio or use SQL commands to check the status of the `nameserver` and `indexserver` processes. Ensure they are running.
SELECT HOST, PORT, ACTIVE_STATUS FROM SYS.SERVERS WHERE SERVER_NAME = 'nameserver' OR SERVER_NAME = 'indexserver';3
For other databases, check the database listener status using native database tools. For example, for Oracle, use `lsnrctl status`.
lsnrctl status4
Verify the database listener configuration file (e.g., `listener.ora` for Oracle, `sqlnet.ora` for Oracle) to ensure it's configured for the correct IP address and port that the SAP S/4HANA application servers are trying to connect to.
5
Ensure that the database listener is running and accessible from the SAP application servers. Test connectivity using `tnsping` (for Oracle) or equivalent tools for other databases.
tnsping <tns_alias>6
Check the SAP system's database connection parameters in transaction `DB59` to confirm they match the actual database listener configuration.
DB594. Examine SAP System Logs for Detailed Error Information easy
Provides in-depth context by analyzing SAP's system logs to pinpoint the exact cause of the communication failure.
1
Log in to your SAP S/4HANA system using SAP GUI.
2
Execute transaction code `SM21` (System Log).
SM213
Filter the system log by date and time to focus on the period when the error occurred. Look for entries related to communication failures, RFC errors, or database connection issues.
4
Pay close attention to the error messages and their details. They often provide specific information about the remote host, port, or program that failed to connect.
5
If the error involves RFC connections, use transaction `SM59` (RFC Destinations) to check the configuration of the relevant RFC destination. Test the connection from `SM59`.
SM596
Check the work process logs (transaction `ST11`) for the specific application server that experienced the error. These logs can sometimes contain more granular details.
ST11