Hey,
i have created today a scenario with Brevo and Templates. In Make you need to define the parameter for Brevo and pass it in the request.
You need to activate “show adcanced settings” → “Params” → Name = Variable name | Value = Content
In Brevo Template you can access the variable in this format {{ params.VariableName }}
If this not resolve your issue, then check in the Template for “verbatim”. this is extra to not use it like a variable and print the content with {{ content }}.
Let me know if it help you to resolve the issue.
King regards
Jamie