I think you basically got it but you are making a clickable link you actually have to follow the link more or less so instead you must wget the link and then end your program! This way you will be redirected to the basic menu and then your program will end if this makes since.
This might actually be another good reason to allow on click events in basic code sliders, buttons, image buttons etc...
Sorry I did not read your post well at first.
LOTS of things 'could' be wrong...
did you use a pull up resistor?
how did you wire it up??
have you tested the sensor with any other code or different microcontroller or esp module?
there are lots of other examples of reading a DS18b20 on here so I would try a simpler test to determine if the sensor is good and to check your wiring.