Creating subscription by API request fails with error status, however subscription created with no hosting

Symptoms

• Creating subscription by API request fails with the error status, however subscription is created with no hosting.
• Symptoms below are valid in case of WHMCS provisioning:
  1. While an attempt to create a service with the username like testusername123456 via WHMCS the following error appears:

     Module Command Error 
      Error code: 1023. Error message: Failed API request: Domain Service Web not exists: domain=example.com, id=35

  2. Plesk allows the creation of a subscription via WHMCS with an existing username.

     During the creation, the subscription is partly-created and the following error occurs in WHMCS:

     Order Accept Encountered Problems Error code: 2204. Error message: Unable to update hosting preferences. The user testuser already exists. Incorrect fields: "login".

     After the username changing in WHMCS and continuing the creation process, it fails with an error:

     Order Accept Encountered Problems Error code: 1007. Error message: Incorrect name example.com. This domain name already exists.

Cause

Plesk bug PPPM-6071. It will be fixed in future updates.

Resolution

For non-WHMCS cases, the only workaround is to remove the partially created subscription in Plesk manually and correct the API request.