Can't Upload from web IDE, but desktop works (Adafruit Feather M0 Adalogger)

Hi, I've tried looking for solutions on this but hit a brick wall. I've tried on 3 different machines, 2 with Chrome on Windows 7 and 1 with Edge on Windows 10. I'm only trying to upload BLINK, so nothing difficult. When I use the desktop IDE there's no problem, so can't be hardware. I know I could stick with the desktop, but it is nice to be able to open the code on different machines so I can edit at home and work.

The full verbose output is attached, but a cut-down version is shown below.

Anyone else have this problem?

Thanks
Paul

Sketch uses 10552 bytes (4%) of program storage space. Maximum is 262144 bytes.

Programming with: Serial

Restarting in bootloader mode

Get port list before reset

[COM4]

Touching port COM4 at 1200bps

Set DTR off

Flashing with command:C:/Users/Paul/.arduino-create/arduino/avrdude/6.3.0-arduino9/bin/avrdude.exe -CC:/Users/Paul/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf -v -v -patmega2560 -cstk500v2 -PCOM4 -b57600 -Uflash:w:C:/Users/Paul/AppData/Local/Temp/arduino-create-agent345510061/Blink.hex:i

avrdude: Version 6.3, compiled on Jan 17 2017 at 12:00:53

Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/

Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "C:/Users/Paul/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf"

Using Port : COM4

Using Programmer : stk500v2

Overriding Baud Rate : 57600

avrdude: ser_recv(): programmer is not responding

avrdude: stk500v2_ReceiveMessage(): timeout

avrdude: ser_recv(): programmer is not responding

avrdude: stk500v2_ReceiveMessage(): timeout

Verbose Output.txt (34.3 KB)

The desktop IDE supports more boards than the web IDE.
Although if you find the board properly listed on the web IDE it should work.
Then again you might have found a bug so moving this to the web specific section.