Thanks for reaching out. Let's sort this out.
Quick questions: what type of Chromecast device do you have? Is the cast button missing on the Hulu and Tubi app? Please reinstall the affected apps and restart your phone. Rebooting your Chromecast and using a different mobile phone might also help.
Just checking in to make sure that you've seen my response. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.