A customer (or Provider on a customer's behalf) placed order to switch plan for their subscription with POA-managed hosting services. Order processing fails in PBA with the following error message for POA:
Change Service Plan failed: Parallels Operations Automation error #error_code #2000, extype_id #270, module_id #ResourceManagement, Unable to upgrade subscription #1000101 to service template #3: migration from resource class 'iis_physical_ds' (resource type #1000001) to resource class 'apache_physical_hosting' (resource type #1000100) is not supported.
Provider incorrectly configured list of allowed upgrades/downgrade for the Service Plan a subscription is based on in PBA - upgrade from Windows-based hosting to Linux-based one is allowed in PBA while it is not supported in POA.
If the current Service Plan of the problem subscription and the target Service Plan the customer wants to upgrade to are based on different POA Service Templates then during provisioning of the order on Service Plan switch PBA sends request to POA to change Service Template for the subscription. The request cannot be completed because current and target Service Templates in POA have hosting resources based on totally different Resource Classes: IIS (iis_physical_ds) and Apache (apache_physical_hosting). POA does not support migration of existing Windows-based webspace to Linux-based and vice versa.
The failed order on Service Plan switch has to be canceled, it is not going to be completed.
Then, Provider has to carefully analyze list of allowed upgrade/downgrade options for their Service Plans in PBA to exclude possibility for a customer to place wrong order on Service Plan switch. The rule to allow switching between plans is simple - Service Plans with Windows-based hosting services may be upgraded to Plans with Windows-based hosting services only, and Service Plans with Linux-based hosting services may be upgraded to Plans with Linux-based hosting services only.
The same rule applies to mail hosting services - POA does not support migration of qmail-based subscrioption to Exchange and vice versa.
After the list of allowed upgrade/downgrade Service Plans is corrected for the Plan the problem subscription is based on the customer may place order on plan switch once again.