Migrate Kraken token to Helix - without secret

Thank you for the extremely quick answer! I can’t get it working it though.

Here’s my example Kraken query:
curl https://api.twitch.tv/kraken/users\?login\=aenduil -H "Accept: application/vnd.twitchtv.v5.json" -H "Client-ID: o9mxxxxxxxxxxoky" -H "Authorization: oauth:b2jxxxxxxxxxxxhyh"

{“_total”:1,“users”:[{…}]}

And I would rewrite this in Helix to:
curl https://api.twitch.tv/helix/users\?login\=aenduil -H "Accept: application/vnd.twitchtv.v5.json" -H "Client-ID: o9mxxxxxxxxxxoky" -H "Authorization: Bearer b2jxxxxxxxxxxxhyh"

{“error”:“Unauthorized”,“status”:401,“message”:“Client ID and OAuth token do not match”}

Could this be due to scopes? Or is there something wrong with my query?