That is one of the most standard "mistakes" English speakers make. Valid are the following versions.
Das ist der Grund dafür, dass...
Das ist der Grund, aus dem (welchem)...
Those are correct because aus and für are the prepositions that are used with Grund
aus einem Grund - for a reason
der Grund für - the reason for
Not really fit for print but not unheard of in spoken is this:
Das ist der Grund, warum (weshalb,wieso)...
And this one doesn't work:
Das ist der Grund, woraus...
It doesn't work because Grund is a defined thing and you can't use that with an open relative pointer like woraus
Compared to English, this way of phrasing ("That is the reason...") is somewhat rare. Maybe because it is a bit lengthy in German. In a lot of situations, especially if the sentences are short, people would use one of the following
Deshalb (darum, deswegen)... that's why/therefore
Von daher... "coming from there" (colloquial but super common and spreading)
Aus diesem Grund... for that reason