Sorry about how long it took to reply. Here's what comes up:
Build options changed, rebuilding all
Upgrading target on COM3 with DFU package C:\Users\meow\AppData\Local\Temp\arduino_build_810670\sketch_dec05a.ino.zip. Flow control is disabled.
Failed to upgrade target. Error is: Serial port could not be opened on COM3. Reason: could not open port 'COM3': WindowsError(2, 'The system cannot find the file specified.')
- bootloader, SoftDevice or application on target does not match the requirements in the DFU package.
- baud rate or flow control is not the same as in the target bootloader.
- target is not in DFU mode. If using the SDK examples, press Button 4 and RESET and release both to enter DFU mode.