Error with Burst plugin

Found the cause. When Burst cals the rest api it loads the back-end minimized, without the other plugins, for performance reasons. So the AIOS plugin is not active at that moment. As the salt is applied dynamically, it is not applied during that rest api call.

A solution for this is to disable the rest optimizer, by going with FTP to your website, and in the wp-config.hp add the following line:
define( 'burst_rest_api_optimizer', true );
=> this line will prevent the optimizer from getting added again.

Then go to wp-content/mu-plugins and delete the file burst_rest_api_optimizer.php

Then all plugins will load during REST API calls as well.