Debug my iOS app and submit the app to the App Store

I have an iOS conference calling app that allows users to join calls of multiple people and share photos and videos within the call. The app uses vonage's opentok framework. However, the app currently does not allow the calls to go through, returning a message that says "There was an error connecting to session Token expired." I need help to fix this issue so that the app works again. I have the full frontend and backend code for this app. Please respond to this job post with the word "boss" so that I know you read this whole description. I just need you to debug the app and then submit it to the app store once it is fixed. I have all the code for the app. I have attached a video showing the problem with the app. Please watch the attached video and in the proposal please explain to me how you will fix this.