RSS sidebar widget not working for Twitter feed

Before this week’s Twitter DDoS, we had an RSS sidebar widget that read our Twitter feed. However, since the attack and since upgrading to 2.8.3, the feed no longer works. I double-checked the RSS address, and it is correct. However, it is returning a message saying it timed out.

I checked the RSS address in an RSS aggregator, and it works fine there. Just not as an RSS sidebar widget on WordPress.

Is this a Twitter issue? A WordPress issue? Does anyone know a fix?