My template is one of the defaults with my custom parameter inline. This is what the text of the email is using the instructions you have mentioned:
---------
Hello {{contact.firstname}},
Plain text emails have minimal formatting so your reader can really focus on what you have to say. Introduce yourself and explain why you’re reaching out.
{{contact.category_total}}
Every email should try to lead the reader to some kind of action. Use this space to describe why the reader should want to click on the link below. Put the link on its own line to really draw their eye to it.
Link text
Now it’s time to wrap up your email. Before your signature, thank the recipient for reading. You can also invite them to send this email to any of their colleagues who might be interested.
All the best,
Your full name
Your job title
--------
You will see the custom parameter “contact.category_total” in the middle. You will also see the standard parameter “contact.firstname” at the top. When I run with the below JSON, the contact.firstname gets populated with Bubba, but the custom parameter does not.
{
“emailId”:38143921416,
“message”:{
“to":"dcornelljames@gmail.com”
},
“contactProperties”:
{
“firstName”:“Bubba”
}
,
“customProperties”:
{
“contact.category_total”:“4071434”
}
}
This is a screen grab of the resulting email:
I have tried
“contact.category_total”:“9999999”
“contact.category_total”:9999999
“category_total”:“9999999”
“category_total”:9999999
None seem to work.