I understand that Hulu is no longer working as it used to, and is indicating that you need to connect to the internet. First, if you're using Hulu while connected to your carrier's cellular network, check to make sure that cellular data is enabled for Hulu.
If you are connected to Wi-Fi, or Hulu is enabled in Settings > Cellular, follow the steps outlined in this article (while the article title may not appear relevant, the steps can help resolve a number of different issues): If an app unexpectedly quits, stops responding, or won’t open
Set whether cellular data is used for apps and services. Go to Settings > Cellular, then turn cellular data on or off for any app that can use cellular data. If a setting is off, iPhone uses only Wi-Fi for that service. The iTunes setting includes both iTunes Match and automatic downloads from the iTunes Store and the App Store.
Let us know if this helps!