Jira API POST and Invoke-RestMethod - json

Question

Using Jira API 2 and PowerShell 5 Invoke-RestMethod I can successfully execute GET, but I keep getting a (400) Bad Request when attempting POST method to create an issue in my project.
$user = [System.Text.Encoding]::UTF8.GetBytes("me:mypassword")
$headers = #{Authorization = "Basic " + [System.Convert]::ToBase64String($user)}
$data = Get-Content D:\scripts\powershell\issue.txt
Invoke-RestMethod -Uri "https://agile.mycompany.com/rest/api/2/issue/" -Method POST -Headers $headers -ContentType "application/json" -Body $data
$data variable is well-formed JSON for Jira:
{
"fields":
{
"project":{"Key": "ITS"},
"summary":"Rest Test 1",
"issuetype":{"name": "Task"},
"assignee":{"key": "myusername"},
"priority":{"id": "3"},
"description":
"||Host Name||IP Address||Comments||
|some-pc|192.168.1.1| |",
"duedate": "2016-09-11"
}
}
I am the project owner, so this isn't a permissions issue.

Answer 1

Get-content is tricky, because it will actually result in a array of strings, where each line in your text file is an object in that array. The best way to get around that is probably using .Net's file read methods instead:
$data = [System.IO.File]::ReadAllText("D:\scripts\powershell\issue.txt")
btw, you can use a regular ps credential object instead of manually building your request header.
On a side note, it's always a good idea to test your api out using a tool such as postman. That will let you verify that you're posting valid json while not having to worry about your code doing strange things.

Answer 2

Problem solved. The issue was that I was CAPITALIZING the first letter of the field names. Apparently, Jira is very sensitive to CASE. Trondh - thank you for the recommendation to use postman. The errors that were getting generated by postman from the failed API calls were very concise.