I tried his account; the feeds loaded quickly without any issue.
@TimBray you could try quitting NewsBlur, then locate the following folder in the Finder and rename or trash it, then re-launch NewsBlur. That will clear out some cached data.
~/Library/Group Containers/group.com.newsblur.NewsBlur-Group
(Tip: you can copy that path and paste it into the Finder’s Go ▸ Go to Folder… menu command.)