Diagnosis
The system is unable to communicate with the application server that isspecified. This is caused by RFC communication problems.

Procedure
Normally, you should see few or no calls with communication problems.However, communication problems do not necessarily represent a problem.For example, CPI-C errors may occur if a server or system is down formaintenance. If the destination is returned to service before the retryinterval runs out, then the tRFC calls and LUWs are automaticallyprocessed.
If the CPI-C errors are not caused by a routine problem such asservicing, then you should check the network connection to thedestination server. In addition to actual network problems, CPI-C errorsmay be caused by:

• An inactive gateway process in the calling or destination System


• An incorrect CPI-C implementation in an external server


• Incorrect data in the definition of the destination in the calling
system (transaction SM59).
You can test connections to RFC destinations in Transaction SM59.
After you have corrected the problem, the tRFC calls and LUWs that wereaffected are automatically processed, if the retry interval has notelapsed.
Otherwise, you can trigger processing an affected LUW by hand inTransaction SM58 (the analysis method for tRFC).
Once successfully processed, calls with communication errors areautomatically deleted from the tRFC work queue, and will no longerappear in this monitor.