无法再闪存或连接到我的 Nucleo 板 (STM32F446)

出于某种原因，我无法再刷新我的Nucleo (STM32F446) 板。它曾经运作良好......我收到以下消息：

openocd -f ./cfg/openocd.cfg -c "program ./build/ch.elf verify reset" -c "shutdown"
Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
    http://openocd.org/doc/doxygen/bugs.html
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
adapter speed: 2000 kHz
adapter_nsrst_delay: 100
none separate
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : clock speed 1800 kHz
Info : STLINK v2 JTAG v34 API v2 SWIM v25 VID 0x0483 PID 0x374B
Info : using stlink api v2
Info : Target voltage: 3.247800
Error: init mode failed (unable to connect to the target)
in procedure 'program' 
in procedure 'init' called at file "embedded:startup.tcl", line 506
in procedure 'ocd_bouncer'
** OpenOCD init failed **
shutdown command invoked

Makefile:210: recipe for target 'flash' failed
make: *** [flash] Error 1

另外，当我发行时：

telnet localhost 4444

我得到：

Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused

当我插入我的 Nucleo 板时，我可以看到它的构建版本等。奇怪。

编辑：插入电路板时 LD1 是实心的。我认为它通常应该闪烁红色。