I've also been having this issue since before DA:V came out as I was wanting to replay DA:I to get in the Dragon Age mood so to speak. While it is unfortunate that you are unable to work the custom world Import it is all the same nice to see that I'm not the only one with this problem!
I do wonder if Dragon Age Keep has been down for a while but it's hard to say, I don't think they've been active on the DA Keep twitter either.
All in all it would be nice if they could still keep up maintenance with the Keep since they still have so many players wanting to use the Keep/Play the older games. (Please let me play with my DAO and DA2 custom world states, I beg of you Bioware 😞)