I created an App in the sandbox, with permissions for SMS and Read-Only. Password-Flow enabled (and private). Client ID is lXbnBnjyQcywt2tt0NFfVA if you want to check.
I plan on accessing it via a FileMaker app API call, but am unable to get the basic credential token, even using Postman. Screenshots from Postman attached...
If I put the grant_type in the body, I get this error:
If I put the grant_type in the header, I get this error:
Any advice would be appreciated...
Thanks!