Cannot create Marketing-only apps on this account

Hi!

I am trying to create a marketingOnly app for Zendesk Marketplace. Before submitting the app as a public application, I would like to try it in my developer Zendesk instance to see how it looks etc. 
When I try to upload the private app through either zcli or the directly in Admin Center I am getting this error: “Cannot create Marketing-only apps on this account”. I have a development account that starts with d3v-. Is that the issue? If so, how should I test my application before submission?

This is how the manifest.json looks
{

"name": "A Marketing Application [Dev]",

"author": {

"name": "octo",

"email": "hello@anemailaddress.com",

"url": "https://anamazingapplication.com"

},

"defaultLocale": "en",

"private": false,

"marketingOnly": true,

"location": {

"support": {}

},

"version": "1.0.0"

}

Please let me know how I should proceed or if there is any other information I can provide,

Best,

Octo