Automatically acquire access token for site hosted in sharepoint to authenticate in on-premise web api

Question

Is it possible to silently, completely without user interaction, acquire access token from login.microsoftonline.com, to authenticate web api running on-premise? I have registered an app in Azure portal. In the sharepoint site there is a js script which is using msal.js.

My msalConfig.js looks like this:

const msalConfig = {
    auth: {
        clientId: "my_client_id",
        authority: "https://login.microsoftonline.com/my_tenant_id",
        redirectUri: "my_redirect_uri"
    },
    cache: {
        cacheLocation: 'localStorage',
        storeAuthStateInCookie: false
    }
};

const msalInstance = new PublicClientApplication(msalConfig);

And in the auth.js I am calling:

await msalInstance.ssoSilent(silentRequest);

But in this line I am receiving such error:

InteractionRequiredAuthError: login_required: AADSTS50058: A silent sign-in request was sent but no user is signed in.

Why is this? I am already logged into Sharepoint online in O365 (this site and scripts are hosted on Sharepoint). Is it possible to overcome it somehow?