Consume a webService published in BC cloud sandbox

Hi everyone,

As you can deduce from my latest post, I’m making developments for integrate BC with external services.

I am creating a function in a codeunit that should return a text variable to an external service that calls it. I’m testing it on postman, but I’m nto able to connect it:

As you can see, I’m getting a 500 internal error. The user and password I’m using to authenticate are the ones I use to log into BC. Tee codeunit is published as a WebService, as I’ve always done:

May be this can be a permission issue or something like that?

I’m quite sure that this should be an authentication isssue. The user in BC is this one:

Which should be the credentials??

Or may be this mark, that I0m not able to mark it to true…