# SAP MMC Webservice Error 21 and 29: How to Diagnose > Source: https://netray.co/erp-help/sap-mmc-webservice-error-21-and-29-sapcontrol-sapstartsrv > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: ERP Help ## Short answer SAP MMC talks to each instance through the SAPControl web service hosted by the sapstartsrv process. A webservice error in MMC means that call failed, typically because sapstartsrv is not running, the instance number or port is wrong, the call is blocked by a firewall or SSL setting, or the OS user is not authorized. Test with sapcontrol from the host and read the sapstartsrv logs. ## Kind error ## System sap ## Erp SAP NetWeaver / SAP MMC ## Module Basis / SAP Management Console ## Query webservice error 21 sap mmc ## Alternate Queries - webservice error 29 sap mmc - sap mmc webservice error - sapcontrol webservice call failed - sap management console cannot connect ## Applies To SAP NetWeaver / S/4HANA application servers on Windows and Linux with SAP Management Console ## Steps ### Diagnose the webservice failure **Items:** - On the SAP host check that the sapstartsrv service for the instance is running (Windows: Services, SAP_; Linux: ps for sapstartsrv). - Test locally: sapcontrol -nr -function GetProcessList. A result list means the service answers; an error text tells you the cause. - Confirm the instance number in the MMC connection matches the actual instance. The HTTP port is 513 and HTTPS 514. - From the MMC machine test the port with a telnet or port check. Open the firewall if it is blocked. - Read the sapstartsrv logs (sapstartsrv.log) and dev_sapstartsrv in the instance work directory for the exact reason. - If authorization fails, check which OS user is allowed to call protected functions (adm or members of the allowed group) and the service's access configuration. - Restart sapstartsrv if it is hung: sapcontrol -nr -function RestartService, or the OS service restart, then retry MMC. ## Sections ### How MMC reaches the instance **Body:** MMC is a client of the SAPControl SOAP web service. Each instance has one sapstartsrv that starts and stops the instance and answers requests such as GetProcessList, Start, Stop and GetSystemInstanceList. If that process is down or unreachable, MMC shows a web service error rather than a process list. The numeric code is a wrapper for the underlying call failure. I would not rely on the number alone: the sapcontrol output and the sapstartsrv log say whether it is a connection refusal, a timeout, an SSL problem or an authorization refusal. ### Frequent root causes **Body:** Service not started after a reboot or patch; hostname changes or virtual host name not resolving; the instance profile or the SAPLOCALHOST value points to an old host; clock or certificate problems when using HTTPS; a firewall rule closing 5NN13/5NN14; and an OS user lacking rights for Start/Stop calls. After a database or OS migration, check that the service was re-registered with the right profile path. On Windows the SAP service account password may have expired. **Code:** - sapcontrol -nr 00 -function GetProcessList - sapcontrol -nr 00 -function GetVersionInfo - sapcontrol -nr 00 -prot PIPE -function GetProcessList (local, bypasses network) ### When to escalate **Body:** If the local call works but the remote one fails, the issue is network or SSL. If neither works and the service logs show profile errors, check DEFAULT.PFL and the instance profile paths. If it fails only for Start/Stop, it is OS authorization. Gather the log lines before opening a Basis ticket. ## Pitfalls - Restarting the whole SAP instance when only sapstartsrv needs a restart. - Assuming the number identifies a single cause; always read the underlying log text. - Using the wrong instance number, especially on hosts with several instances. - Opening firewall ports broadly instead of limiting access to admin hosts, since SAPControl can start and stop systems. ## Ai Angle An assistant on your own infrastructure can read the sapstartsrv log excerpts you paste in, compare them with the instance profile, and suggest the likely cause with the commands to verify. It does not connect to production hosts on its own and never runs start or stop commands without human approval. ## Faq ### What is sapstartsrv? **Answer:** It is the SAP start service process for an instance. It exposes the SAPControl web service used by MMC and sapcontrol, and it starts, stops and monitors the instance processes. ### Which ports does SAPControl use? **Answer:** HTTP is 5NN13 and HTTPS 5NN14, where NN is the instance number. For example instance 00 uses 50013 and 50014. ### How do I test without MMC? **Answer:** Run sapcontrol on the host: sapcontrol -nr 00 -function GetProcessList. It uses the same web service and prints a readable error if the call fails. ### Does restarting sapstartsrv stop SAP? **Answer:** Restarting the service does not by itself stop running work processes in most setups, but test in a maintenance window. Check the instance state with GetProcessList afterwards. ## Search terms webservice error 21 sap mmc, webservice error 29 sap mmc, sap mmc webservice error, sapstartsrv not running, sapcontrol GetProcessList, sap management console error, sap instance 5NN13 port, sapcontrol authorization --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json