Fail more gracefully when you get "author does not exist" messages

[boonebgorges]

When someone sets up EPL using the dirty database and then switches to MySQL (or does some other major config change that results in lost EPL data), WP can still be caching what are now incorrect tokens for pads and user IDs. There should be a better mechanism of detecting these problems, and possibly a one-click button for flushing all old EP data on the WP side, so that it can properly refresh.

[JohnMcLear]

+1, something that deletes cached data on failure would be ideal. Etherpad should return a failure so it should be easy to execute based on this. Heh this is basically what's tripping me up today :) I will take a look see if I can resolve it.