The server part reports about two types of errors to the client software, which are checkup errors and execution errors (if it comes to executing the requested operation).
If an error of any type occurs, its description returned by Plesk server always contains the following parameters:
An error description is defined by type resultType in the
common.xsd schema (in most cases) or by types based on it (depending on the operator).
Incoming HTTP packet passes through a number of check-ups on the server side before it is considered valid and ready for execution. Here are some of these check-ups:
Any of these check-ups can fail which makes further checkups and command execution impossible. Since the server side has got stuck at one of the preliminary checkup steps (i.e., it has not come to executing the requested operation yet), the response packet is formed with the following elements:
For example, the response received from Plesk API RPC server at the attempt to use a non-existing version of the API RPC protocol looks as follows:
<errtext>API RPC protocol version not supported.</errtext>
The list of error codes supported by Plesk API RPC server is presented in the Error Codes section of the Plesk API RPC Protocol Reference.
If all checkups have been passed through successfully, the selected agents try to execute the requested operations in series. If any operation fails, the related agent reports about the execution error. All reports are gathered by Agent Engine which forms a response packet based on the output XML schemas. E.g., if failed to create a domain, the domain operator will form an error response using the
<errtext>Failed to add domain.</errtext>
Note: Response packet can report about more than one execution error. This is possible if the incoming packet requests for more than one operation and some (or all) of them fail. Also, beginning from version 22.214.171.124 of API RPC, the response packet can contain multiple operator sections if the incoming packet requested for operations on multiple Plesk objects.