I am also experiencing this, and I have tried various browsers and both Linux and Android, even though it seems a server-side error.
In my case, the exports fail or partially succeed. In the latter sense, I get some of the articles, but not manuscripts or prose. I'll run it again and see what happens, though multiple requests can cause jobs to "overlap" and interrupt each other. So, error or no error, I will run it once and check back tomorrow to see the result.