why my esp8266 can't refresh the web page

hello everyone

Recently,I buy a nodemcu lua v2 and want to a little project want it.

I want to use this board with dht11 to record the house temperature and humidity.

But I have some problem occurred.

That’s my web page work little time and it broke.

I can’t refresh the page anymore.

hope someone can help me,thank you very much.

that’s my code.

btw,My English is poor,very sorry about that.

dht11wifi_v2_17_2_8.ino (3.11 KB)