gRPC basic auth encoding

Doing the gRPC request using basic auth, I’m setting the username and password, and the server responds with basic auth token is not valid base64: illegal base64 data - indicating that the credentials are not encoded.

Copy pasting the same request and credentials to Postman work, it does encode the basic auth header I guess.

I’ve tried encoding the password alone, etc. But as far as I know, the whole credentials must be encode, for example, here https://www.rfc-editor.org/rfc/rfc2617#section-2

Could you please let me know if I can configure it somehow in Yaak or is this something has to be adjusted on the app side?

Thanks!