Not now. And I just tried again in DTTG3, same error.
Tried with latest DTTG update (3.0.3 I think?), same error when trying to “purchase” the Free Upgrade.
I finally actually purchased the paid Upgrade… which worked. ¯\_(ツ)_/¯
We are looking into this as it is only occurring with a few people who are trying to exercise the free option.