Discourse to Discord Webhook

I am getting this error when sending a ping or a new post is created. Any help with what is happening here?

I tried both a public and private channel; same response.

Status: 400

{"code": 50006, "message": "Cannot send an empty message"}

config.php

$discord_webhook_url = 'WEBHOOK_FROM_DISCORD';

$discord_embed_color = '#HEX_VALUE';

$discord_embed_thumbnail_url ='https://DOMAIN_NAME';

$discord_embed_footer_icon_url = $discord_embed_thumbnail_url;
$discord_embed_footer_text = 'CUSTOM_STRING';

$discord_embed_timestamp = true;

$discourse_payload_secret = 'RANDOMLY_GENERATED_STRING';

$discourse_url_protocol = 'https';

$discourse_url_domain = 'forums.domain.com';

$discourse_path = '/';

Discourse Settings

Payload URL = DISCORD_APP_WEBOOK_URL

Content Type = application/json

Secret = RANDOMLY_GENERATED_STRING #same as above

Events = All events, or, all individual events checked

Check TLS certificate of payload url = checked

Active = checked