jlink调试

求大佬帮忙！！！！
jlink调试出现如下错误怎么解决：
Warn : Failed to retrieve serial number: LIBUSB_ERROR_TIMEOUT.
Warn : Failed to send data to device: LIBUSB_ERROR_TIMEOUT.
Warn : Failed to send data to device: LIBUSB_ERROR_TIMEOUT.
Error: Sending data to device timed out.
Error: transport_write() failed: timeout occurred.
Error: jaylink_get_firmware_version() failed: timeout occurred.