No blocks showing, cannot save links frontend

Supposedly, using the EB composer, I can select blocks to drop into the posts. I can't - there are none showing. All I see is a message asking me to select a block, but there's nothing to select.

Second, I cannot add a link from the frontend, though I can do if I go into the backend. The link block appears when I highlight the text and allows me to enter the URL, but saving it causes the link (and sometimes the highlighted text as well) to disappear.