It might be worth going back into the debug configurations, deleting the reference to the DSTREAM (USB:0000706), and browsing for it again. Does that help?
If not, I also recommend checking that you have the latest firmware installed (go to Window -> Show View -> Debug Hardware Firmware Installer).
See also https://community.arm.com/developer/tools-software/oss-platforms/w/docs/287/common-issues-using-ds-5-with-juno
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