Parameters of cProjects message: ID = &1, number = &2, variables &3 &4

What causes this issue?

The cProjects system has triggered a message with the parameters
indicated.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the message in the cProjects system, using the parameters
indicated.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.