Helpful tip - if you get the transaction broadcast error message, check to make sure there was an actual error. Sometimes, it fires as a false positive.

I just joined steemit (hi all!), made my first post (https://steemit.com/web/@kleingtm/how-much-do-websites-cost) and had the same issue.

It turns out, the post actually HAD gone out to the blockchain, but the code must not have handled the response correctly.