you should get xpub key using third-party https://kkxpubexporter-mv2ds3ul8.now.sh/
[1] https://keepkey.zendesk.com/hc/en-us/articles/360001411510-How-Do-I-Get-xPub-on-OS-X-
[2] https://github.com/keepkey/keepkey.js/pull/24
or better to get your xpub key by connecting your HW with electrum. After you got it, you have to import the xpub key to get the address but that is as watch-only wallet