I note that all the errors from your screenshot contain Cover Art Archive URLs. This is consistent with the older screenshot, where you did get some information about the releases – apparently just fetching the covers did not work.
The CAA servers did have a spell of dizzyness some days ago. I think it passed, but as @mfmeulenbelt mentioned, most ’brainz servers are not totally reliable at the moment.
Personally, I’d not lay off tagging just because there are some releases where you’d have to retry. Remember that, once your files have MBIDs attached to them, loading them into Picard at a later date (for example to get covers or information that was missed in the first run) is quite hassle-free.