# Interprocess Comunication codes

**500 - Missing Target Application**\
When two processes are communication to each the application of the target process must be already defined. If the application does no exist then this error arise because the target process can not be identified.

**504 - Missing Target Process**\
Same as 500 with a different situation the application exist but the process does not.

**508 - Missing Gateway or Event**\
The application and the process has been identified but the gateway event or the event does **not** exist in the process definition.

In order to fix **500**, **504** and **508** the expecification of the **Sender Process** must be changed at the **Send Task Definition** inside the **BPMN** tool and importer again.