Sorry for the whole topic, just realized I had got the wrong Uploadspeed (921600) .
Changed it to 115200 and everything is working

Hello,
I tried to upload my code, everything worked but when I opened the Serial Monitor, it showed me that Issue:

Brownout detector was triggered

ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv ...