[Plugin: Twitter Widget Pro] Can't save username

I have been having the same problem, both with this plugin, and the Twitter widget that is part of Jetpack. What on earth is going on…it’s driving me mad!

If the username isn’t saving, it’s likely because there’s some other problem on the widgets screen. Try disabling all your other plugins and try it. If it still doesn’t work, it’s something in your theme. If it does work, enable your other plugins one at a time to find the one causing the issue.

The “No feeds available” is likely caused because you don’t have a valid username in there, but it can also happen because you’ve gone over your API request limit. Unfortunately the limit it fairly low (150 per hour), and while Twitter Widget Pro only makes a max of 20 requests per hour it’s pretty common that other sites at your shared host are sucking up all the requests (or possibly that your IP has been blacklisted at Twitter, again likely the cause of another site at your host).