@peak.moderator, the failed postings have when I have been logged in via Steemconnect. I can use all the SteemPeak features; save drafts, insert photos, format text... but when I click to publish, that error message shows up.

It did NOT show up here because (i'm thinking) this was a super simple and short post with no graphics footers and so on. But I don't know.

This is a pretty important issue for me, because I want to completely move away from using the terms "Steem" and "Steemit" when describing what I do to fellow bloggers who could become community members... I just want to be able to say "I'm blogging on a site called Steempeak."