Contact support, I don't know why you don't use it. They are fantastic. (Well I don't know if maybe you can't because is not Jarvee and it's MassPlanner)
I had a similar problem and they helped and then Yesterday I had exactly yours and I tried the same solution and it worked. But do it under your responsibility, and preferably contact support first.
You open the browser, keep it open for 10 min. Then click on advance settings and click on "use alternative browser blabla..."