Why doesn't the FC-75 charging module work?

Question

Electronics

Hello. This might be a stupid question, but I couldn't find anything on the internet about this.
There is an STM32 board and there is an FC-75 charging module. There is also a lithium battery with already installed protection on board 400mAh 3.7V.
I connect it to FC-75 (BAT+, BAT-, that's right) and STM32, respectively, to IN+ and IN- (if it's important, I connect the solderless part with legs, where the programmer is usually inserted into the back) to 3.3V.
In general, I connected it (via USB, from a computer), I'm waiting. After about 30-40 minutes, the blue indicator lights up. I turn it off - and everything goes out. I connect - again the red indicator, and after 5 minutes the blue one. I turn it off - it doesn't work. Why? I expect that when the USB power is turned off, power will be supplied to the board, and it will work.

Answer 1

how is FC-75 related to stm32?? it's just a linear voltage regulator for charging a lithium battery.
The power to the board must be taken from the lithium directly.
send back, i.e. take from lithium and give 5 volts to usb, FC-75 is not scientific.
Yes, and can not, because it is not impulsive.