STM32duino keep leaving the COM Port

[kirito2908]

Hello,

I Was On A Project With STM32duino (Blue Pill) Using Arduino IDE. I Have Already Flashed The Bootloader And It Was Working Fine At First. The Sketches Were Getting Uploaded At First But Suddenly Is Started Having Problems And It's Keep Leaing The COM Port. When I Reinstall STM32 Boards From Arduino And Reinstall The Drivers, It Shows Up Again But When I Try To Upload The Sketch It Leaves The Port Immediately. Here's The Error Message,

Sketch uses 12804 bytes (19%) of program storage space. Maximum is 65536 bytes.
Global variables use 2064 bytes (10%) of dynamic memory, leaving 18416 bytes for local variables. Maximum is 20480 bytes.
maple_loader v0.1
Reset via USB Serial Failed! Did you select the right serial port?
Assuming the board is in perpetual bootloader mode and continuing to attempt dfu programming...

Resetting to bootloader via DTR pulse
Searching for DFU device [1EAF:0003]...
dfu-util - (C) 2007-2008 by OpenMoko Inc.
This program is Free Software and has ABSOLUTELY NO WARRANTYCouldn't find the DFU device: [1EAF:0003]

Does Anyone Have Any Idea Of What I Should Do ? Any Help Is Appreciated. 
Thanks For Reading This.

[Tesla DeLorean]

 Check BOOT0 pin state.

Consider asking on a forum supporting the platform. Coverage here probably not high.

[kirito2908]

Thanks @Tesla DeLorean For Your Reply. The State Of BOOT0 is At '0'. 

[kirito2908]

Should I Ask About This In Arduino Forum ?

[Tesla DeLorean]

Or the one for STM32 Arduino and the developers of that fork.. would seem to be a better venue

[UnderGnd]

USB CDC have to be enable to have the COM port.