Either I’m incompetent (quite likely) or this beta wants you to re-login much too often. Here for instance, it wanted me to log in again simply to upload a picture.
Edited to add:
Not sure how I’d do that since I’m already logged in. So it’s letting me post, but not letting me upload a pic.
FWIW, in an iOS/Safari environment. Also, when I went to edit the post, the tags I had entered initially were gone.
Second edit:
Duh. My mind was in beta mode, forgot that this would post to the Steem blockchain as a whole and not just the beta testing site, so neglected to set this to decline payment or at least assign @steem.dao or @null as 100% beneficiaries.