I'd like to bump this up to the top as I have the same issue.
Horizon 7.10. Connection Servers/UAG's upgraded fine, but the JMP server won't register. Upgraded from 7.9 to 7.10 so not a huge swing in versions.
I have completely uninstalled and reinstalled the JMP server, but it will not register in the horizon console.
Verified all the SSL certs were OK. The 404 page at least shows that the cert is working and valid.
When I try to hit /xmp/jmp/login I'm getting:
Any help would be appreciated.