OAuth2 User Agent Flow API Authentication in API Connector

Greetings Bubblers! I’m currently facing an obstacle where I’m unable to transmit the access token to an OAuth2 User Agent Flow API via the API connector of my application. The process entails me authenticating myself to my platform by using “sign in with SSO” in the test environment, and subsequently transferring the refresh token and access token to the API connector in order to make the required API calls. I’m wondering if there is an easier way to authenticate my API to do away with " Your token is not valid any more. You should sign up again in run mode to get a token to set up and modify your calls" or if there are any solutions to get it working again, as it has been functioning properly for several weeks but has stopped working this week.