Hello Mihaela,

I assume you are testing with one of the example scripts generated when testing the API, these scripts all use admin:admin as username/password but you have to update with a real username password combination. (so it has to be a user that is in the instance and has rights to do the things you want to do.

Link to the documentation (ensure that you use the correct version, this is for Istanbul) REST API security

Kind Regards,

Gerrit Kuilder

Technical lead Integrations EMEA