Code 400 error on version 2.5.5

I’m using Postman SMTP 2.5.5 and received the following email with errors. Any thoughts or suggestions are greatly appreciated.

Code: 400, Message: Bad Request, Body: {“errors”:[{“message”:”Unless a valid template_id is provided, the content parameter is required. There must be at least one defined content block. We typically suggest both text/plain and text/html blocks are included, but only one block is required.”,”field”:”content”,”help”:”http://sendgrid.com/docs/API_Reference/Web_API_v3/Mail/errors.html#message.content“}]}