The Purpose of this page is to provide further information regarding the error messages “error when opening an RFC connection” with tRFC entries (transaction /SM58).
This page explains the reason for the tRFC failures and how to get rid of them.
The error cause
The "Error when opening an RFC connection" error message is a result of the affected RFC destination (in this example, the TSTCLNT100) not working when an entry was being processed. This might happen due to intermittent network glitches or any network issue.
First of all you need to ensure that the RFC destination affected (TSTCLNT100) is working fine (results of the connection test):
Then, if there is no error with the RFC destination, you’ll be able to reprocess the failed entry manually (in Transaction /SM58 => Edit => Execute LUW). You can also schedule the report RSARFCEX to run at regular intervals in your landscape. The report RSARFCEX will reprocess any failed entry in the tRFC layer. Therefore it is always recommended that this report run at very regular intervals (for example every 2 minutes) to reprocess RFC requests which might have failed due to an intermittent network glitch.
SAP Note 1483845: Using the report RSARFCEX