Make sure i2c is enabled.
And if it is, it might be a bad connection - if you soldered the headers yourself make sure they’re all good joints, and check that the Hat is fully attached.
Thanks but neither solves the problem. Still need help.
More information, more words would probably help at this stage. We’re having to guess a lot of stuff based on a post consisting purely of a screenshot!
So; what HAT? What Pi? Was it bought with headers or did you solder it yourself?
What OS do you have installed? How have you installed the drivers, and did you get any error messages in the process?
Do you have any other devices / software installed?
Do you have another Pi you can try it with?
Are you able to post a (clear, in focus!) picture showing the HAT mounted on the Pi and (if you soldered it yourself) the header soldering?
(that’s probably enough to start with…)