Tx LED always ON on Croduino NOVA


I am new to this Forum and Arduino. I bought Croduino NOVA (same as Arduino boards, but with ESP8266 on the board itself). Here is the link to it: Search results for: 'croduino-nova' . I was programming it for 2 days, everything worked perfectly, i tried lot of basic codes (Blinking LED etc...) and everything was fine. I am using Arduino 1.8.2 IDE on Windows 10. Today, i tried to upload a code to board and after uploading tx LED was always ON and didn't want to turn off. I tried to reinstall drivers, writing empty code and upload it, but nothing. Upload is successful, no errors shown, but after upload tx LED turns ON and that's it. Can anyone please help? I attached a photo where you can see that tx LED is always on (white light next to PWR) and blue light next to ESP8266 chip.