Cannot connect to J-Link via USB on SES for ARM 3.40.

Error executing NovelBits Gateway app on nRF52840 with SEGGER Embedded Studio. "Cannot connect to J-Link via USB"

Running the SES for ARM 3.40 on Ubuntu 16.04 64 bit. The device appears as a removable disk 'JLINK' in the Linux file explorer.

Any help?