Content Builder Application Internal Server Error upon navigation

Should this error message be received, browser settings will likely be the culprit.  A specific indicator that the problem is specific to the browser settings will be shown in the URL bar:




Once this has been confirmed, the problem can be remedied through browser settings (settings included apply for Google Chrome but other browsers will have similar options):

• • Navigate to Preferences (Settings)
  • Scroll down to Privacy and Security then click into Site Settings.
  • Below Permissions click into Cookies and site data.
  • Disable the option Block third-party cookies.
  • Navigate to Content Builder through 

Salesforce Marketing Cloud > Email >  Content and confirm that you are now able to successfully open the Content Builder application.

The other reasons that might cause this issue are as below:

1. Cookies and Cache: Clear your browser’s cookies and cache, then try accessing the application again.
2. Network or device: Try accessing the application using a different network or device.
3. Ongoing Incident/Issue: Check the  trust status site to see if there are any active incidents affecting the stack or database.
4. IP Allowlist: Ensure that the Marketing Cloud IP addresses are properly allowlisted, and add them if they are not already included.