try({OpenML::populateOMLCache(task.ids = c(3891, 9950, 9981, 14966, 34536))})
Downloading 'tasks' to cache.
Downloading from 'http://api_new.openml.org/v1/task/3891' to '/tmp/RtmpeMTT5l/cache/tasks/3891/task.xml'.
Error in doHTTRCall(method, url = url, query = list(api_key = conf$apikey), :
ERROR (code = <NA>) in server response: <NA>
Server returned a HTML document!