Blank results with cross process...

I went to cross process some expired E100 film that I got free when buying a "debonair" camera from FFP. Unfortunately It ended up blank....I don't think the film was exposed to light as its more not exposed rather than the "black/brown" of inadvertent exposure. I'm pretty sure I did the 3 1/2 min of dev, 6 1/2 of blix and I was careful with the temperature (there was a long break between prewash and developer as the prewash was at temp but the dev wasn't quite there yet.) One suspect is the developer could have gone bad (it was very dark) or could it have been the long break between prewash and dev? I'm leaning towards bad developer. Thoughts?

Throw a scrap of film in the dev if you have any left, it should turn black. If not and your, sounds like C41 dev, is likely dead.

Are there any edge markings or is the film totally blank?

It's totally blank which makes it even more seem like it was bad developer. I thought unicolor developer had a decent shelf life but it's possible I didn't have the container closed properly and air got in.