Everything was fine. SIM800L and FTDI modules were working fine. Next day with same configuration modules didn't respond. I connected STM32 TX (PA9) pin to oscilloscope. So it is sending something.
Ok, I thought maybe FTDI went down so I tested with Arduino. It worked perfectly. Then I tried STM32 TX connect to Arduino RX. There are the results. A few symbols for some reason received wrong. FTDI does not respond to this and also Sim800L because it doesn't recognized as serial communication?
Here are my code: link