No device found when uploading sketch

using web IDE with MKRZero. trying to upload the blink sketch, this error keeps helping

arduino-builder/arduino-builder -compile -core-api-version 10611 -build-path /tmp/305096025 -hardware arduino-builder/hardware -hardware arduino-builder/packages/cores -tools arduino-builder/tools -tools arduino-builder/packages/tools -built-in-libraries arduino-builder/latest -libraries /tmp/049827170/pinned -libraries /tmp/049827170/custom -fqbn arduino:samd:mkrzero -verbose=true /tmp/049827170/Blink

Using board ‘mkrzero’ from platform in folder: /home/admin/builder/arduino-builder/packages/cores/arduino/samd

Using core ‘arduino’ from platform in folder: /home/admin/builder/arduino-builder/packages/cores/arduino/samd

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421] → [/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]

Wait for the port to reappear

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421] → [/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]

timeout

Flashing with command:/Users/descobar/.arduino-create/arduino/bossac/1.7.0/bossac -i -d --port=. -U true -i -e -w -v /var/folders/l0/9k5wn5c55dx_fby9sl34556m0000gn/T/arduino-create-agent524804209/Blink.bin -R

Executing command: exit status 1

Hi there.

Going to suggest you read this first then add any additional information that you can.

The error message is a good start but too many missing pieces of information right now.

Overall please let us know what Browser and OS you are using so we can try to reproduce. I just tried on Mac OSX Sierra and Chrome and it is fine.

Do you have the desktop IDE or other software that might be using that port? Do you have the Serial Monitor open?