Error (Status of 500) and X-Frame-Options with google apps script redirect function

Question

I am currently trying to build a web app with google apps script, and I have implemented a login function. The login happens as it should, but I then try to redirect the user to the dashboard of my web app. The current code for the dashboard is the basic code for a new HTML file within apps script with a h1 title, so there are no issues with it.

In my login.html file, this is how it should redirect the user to the dashboard page:

function onLoginSuccess(sessionId) {
      if (sessionId) {
        console.log('Success')
        console.log(sessionId)
        window.location.href = "dashboard?sessionId=" + sessionId;
        console.log('Success')
      } else {
        alert("Invalid email or password. Please try again.");
      }
    }

I have tried an url with "dashboard.html?sessionId=" +sessionId and I get the following error in the F12 console: Failed to load resource: the server responded with a status of 500 () I then tried an url without the html "dashboard?sessionId=" +sessionId and I now get the following error: Refused to display 'https://developers.google.com/' in a frame because it set 'X-Frame-Options' to 'sameorigin'. I then tried adding .setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL); with my return HtmlService line, but I still get the error.

With both URLs, both success and the session ID get called into the console.

Is there a way to fix the issue? Maybe another way to redirect the user, or just a way to fix the error?