Hi Konstantinos,

Simply make your app "Public" and choose 3-legged authorization flow for your app so anyone can login with their own credentials.

Please read this getting started doc for details information
https://developer.ringcentral.com/library/getting-started.html#CreateYourApp
Also check out this tutorial for implementation of OAuth in JavaScript
https://github.com/ringcentral-tutorials/oauth-nodejs-demo

+ Phong

---

Thanks. That's what I had done. 

Actually the problem was that when I tried with another dev account I got the message that this user could not be found. After creating an app in the new Sandbox account it said something along the lines that a new sandbox account was created and it found my user.

Additionally, it kept saying this user was not verified and I had to manually reset my password for the user to be considered verified.

---