Encountering error in "News" and "Events" section of training

I used this https://www.youtube.com/watch?v=Jzuw3uWtzzI&t=2815s tutorial and done all the things as shown in the video, but then also the "News" and "Event" section is not updating. The references for the same are given below:

The frontend is not updating and backend is updating as shown above. Can anyone help me resolve this issue?