As you will see from the answer above "the" is part of the primary translation. There was one version in the incubator without "the" (I don't know how it got there) but I have removed it now.
Why the Duobot rejects a perfectly correct answer in favor of a secondary and incorrect one is something we have never been able to explain. Was this on a Strengthen skills exercise? Thanks for the correction.
My spellcheck doesn't have "videocall." I tried "Videocalling is great" but that was rejected. I don't know if it was the missing 'the', 'great' or 'videocalling' that was wrong, so this time i just went with what it said it should be, but as 'video call', which worked, since spaces are sometimes ignored.
"Video call" is included in the correct translations and I think it's the more correct of the two, if not the only one. We usually translate sentences that begin with gerunds using "Το να...+verb (usually in the 2nd person singular)". In this case: "Το να κάνεις βιντεοκλήση είναι τέλειο".