oAuth 2 Get new Access Token

Newbie here using Lulu Developer API (for book publishing).
https://developers.lulu.com/documentation

Selecting authentication type as oAuth2. On the get new access token screen, there are form fields for client ID and client secret. However, Lulu requires submittal as a concatenated base64 string. I can’t copy and paste individual ID and secret strings from their site and paste them in.

Is there a work around?
Thanks! Mark

I get an 401 unauthorized error
"error decoding signature" when I use base 64 decode.

Hi Mark,

Seems like Lulu Developer API does not use Oauth2 but OpenID Connect. This is not yet supported in Postman.

As a workaround, you should be able to send a request to token endpoint by providing the authorization yourself. For this, you don’t have to manually encode/decode values. Just use the basic auth and put the clientId in the username field and the clientSecret in the password field. When you send this request, Postman will automatically send the Authorization header with value "Basic $Base64(username:password)" which is what LULU api expects.

I hope this helps
Harendra