REST API POST call works in postman, but not from C# application

[Michael Cochrane]

I'm making a POST call to https://<site>.atlassian.net/rest/api/3/issue 

In the C# app, the JSON payload is pretty basic:

{"update":{},"fields":{"summary":"Test from c# migration app","issuetype":{"id":"10001"},"project":{"id":"10000"},"description":null}}

where issuetype and project are valid ids. I get the following error:

{"errorMessages":[],"errors":{"issuetype":"Specify an issue type"}}

When I paste the same payload into Postman, the POST is successful - all headers are the same and I'm using the same basic auth token. Any ideas why I'd be seeing these errors?

[Michael Cochrane · Accepted solution]

Resolved - realized that issuetype Ids were not global, and may be different for each project