@gsrfan01 The error happens because the joining host has TLS certificate checking enabled for pool connections while the joined host don't.
This mismatch happens because on fresh installs TLS certificate checking is enabled, while for updates from previous versions is not.
To enable TLS certificate checking in a pool simply running xe pool-enable-tls-verification
.
The emergency command is not needed in this case, it's useful to re-enable certificate checking in a single host after is has been disabled using the emergency disable