Drupal\Core\Entity\EntityStorageException on saving a node with Mediaflow media attached

Problem/Motivation

After adding a media to the site using Mediaflow form I was trying to use that media on the node and got an error on node save.

Drupal\Core\Entity\EntityStorageException: Client error: `POST https://customerapi.mediaflowpro.com/1/files/multiple/usages?id=2939350&...` resulted in a `400 Bad Request` response: {"status":400,"error":"400-0000","errorMessage":"Invalid JSON data","detailedErrors":null} in Drupal\Core\Entity\Sql\SqlContentEntityStorage->save() (line 817 of core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php).

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes