Gmail Service Account dont want authenticate

[NonozgYtb]

Hi everyone,
After several long hours, I still cannot use my service account for Gmail. I'm a Google Workspace customer, but whether it's through JWT, OAuth, or other things (some of which the current version no longer supports), nothing helps and I get just errors. I don't really know what to do to be able to access information (via an OAuth client for my account only its walking) on ​​the gmail accounts of my members.
Can I have a (actual) solution ?
Thanks a lot.
PS: sorry for the text pad but it's late and I'm exhausted and quite frustrated with this problem

[NonozgYtb]

Hi,
After a lot of research, I found a solution that works (I use the promises):

const credentials = require("./credentials.json") // File downloaded with the Service Account Keys
const getGmailAuth  = async ()=>{
       const auth = (new google.auth.JWT(
            credentials.global.client_email,
            null,
            credentials.global.private_key,
            GMAILSCOPES,
            person
        ))
        await (new Promise((resolve, reject) => {
            auth.authorize((err, tokens) => {
                if (err) {
                    reject(err);
                } else {
                    resolve(tokens);
                }
            });
        }))
        return (auth);
}

Good bye !

[frozen-a-b]

Hi @NonozgYtb ,

I think I ran into a similar issue

What is person in your code?

[NonozgYtb]

Hi @NonozgYtb ,

I think I ran into a similar issue

What is person in your code?

person is a string with an email like :

const person = "firstname.name@mydomain.com";