When logging in with K2 Trust for Azure AD on SharePoint online via the Script Editor web part, the worklist will display "This content cannot be displayed in a frame" after logon.
The Script Editor web part will not be available for any users to action tasks.
To correct this issue you will need to determine what Authentication is required.
It is expected to see this error in the Script editor web part if you are not logged in with SharePoint Credentials, so you need to sign out properly from SharePoint Online.
It is recommended that the K2 Smart Form Viewer web part be used as this is integrated with K2 Authentication.