Perhaps you have a broken widget, try validating all your widgets in your model. Also check your developer tools by pressing f12 when loading the page, check if you get any errors on loading the page.
IE8 is a wild gamble for a lot of "modern" Apps.
did you check the App in alternative browsers? if so, do you experience the same error ?
If it is NOT browser-related, check your navigation ! Is it possible you have role-based landing-pages? and forgot to define one for the role you are using to test?
When still "modeling" your App it is often convenient to make sure ALL roles have a separate landing-page, for reference