trying do Sign In validation with fetch. and server return me null

I learning Full Stack , and have problem with HW..
The sign Up send all data to database great, But when I try find user from database (To sign In) its return me always null.
In database I have user with mail [email protected] and its not find him.
Without fetch its working great, But I need use fetch here (By the homework)
Tried find some fetch sign in tutorial, but its not help.

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[1]: https://i.stack.imgur.com/XIdfF.png
[2]: https://i.stack.imgur.com/x1Sz4.png
[3]: https://i.stack.imgur.com/bBMh9.png