Related to https://community.atlassian.com/t5/Jira-questions/Attaching-files-to-Jira-issues-from-Confluence-offline-user/qaq-p/888576
I'm looking to have users register anonymously with information and upload files via confiforms confluence form to JIRA. I tried to follow above, but I'm guessing this is for server (I don't think on cloud I can just add macros) but getting 415 error when trying to attach the file (after ticket has been created, added to confiforms page).

With form above I'm able to capture data, create JIRA ticket (not shown), and then create confiforms entry (first IFTTT) with jira key and attachment.
The second IFTTT form is to add attachment. I have tried various headers, with and without content, with and without 'Set parameter name' to file, and with different api path (/rest/api/latest/issue/... vs /rest/api/2/issue/...). Most errors are coming back 415.

Not sure where to turn here.
Thanks for any help