[SmartCrawl Pro] Smartcrawl causes website to go blank

My client hosts her website with wordpress and subscribed to Jetpack. I have installed WPMUDEV and use several plug ins. I have now discovered that Smartcrawl causes an error. When activated the website doesn't load. When de-activated it's back. I'll grant you access. Feel free to activate and de activate to see what happens. As long as you de activate it again when finished and can't resolve it.

Thanks for your helps
Ellen