The first step is to check your browser and browser version number to verify it is compatible with your application and Cortex. For the browser requirements statement: Cortex Browser Requirements
If your Web application/Cortex is behaving unexpectedly with a supported browser, you may need to clear your browser’s cache to ensure that your browser is utilizing and displaying the most up-to-date versions of your application. Refer to the following Solutions for your browser:
Clear Cache - Internet Explorer
If you are still having issues, refer to the solutions for the specific error message you are receiving.