A 'TemplateModel' is required when using a template to send an email.

[SimonVillage]

I am getting this error for templates not using any template model

This message is using a Postmark template.

Alias: "password_change"
Model:
{
}

Use the #prerender method on this object to contact the Postmark API to pre-render the template.

Cheers,
Your friends at Postmark
Postmark::ApiInputError: A 'TemplateModel' is required when using a template to send an email.

[SimonHausdorf]

as a workaround

self.template_model = { tmp_fix: '' }

can be used

[nickhammond]

Hey @SimonHausdorf,

Sorry about that, I've updated the wiki article to mention that a template model should be specified. A TemplateModel is a required attribute, here's a bit more information around our template syntax if you're curious.