Custom JWT Authentication for SPA

I’m trying to use Auth0 as third party for authentication with a SPA application.

For that I understand that I need to use the Bearer JWT to avoid the CORS errors.
But I also found in the forum that Mongo Realm doesn’t support to find an array of audience in the aud claim. I’ve got this error in my logs : “json: cannot unmarshal array into Go struct field accessTokenData.aud of type string”.

How is possible to correctly use JWT coming from Auth0 with the Mongo custom JWT authentication? If I use the header jwtTokenString instead, I go back to the CORS error. My request are directly made from the SPA.

Really thanks for your help.