Plesk

Unable to create a new mailbox on a server with SmarterMail: Incorrect Content-Type: must be textual to extract_string, JSON to extract_json

Symptoms

Updating SmarterMail to version 100.0.8495 or higher breaks the integration. For example, new mailboxes cannot be created:

mailmng failed: Incorrect Content-Type: must be textual to extract_string, JSON to extract_json.

Cause

In the recent SmarterMail update API, which was used by Plesk to manage mail server was seriously reworked, The task to rework how Plesk manages SmarterMail has ID PPPM-13966.

Resolution

To apply a custom fix:

  1. Download the attached custom fix.
  2. In Plesk services Monitor: stop Plesk Management Service
  3. Unpack files from the attached archive to %plesk_bin% folder
  4. Start Plesk Management Service