The bosh is activated in by default as @Moul indicated in Bosh support for metronome. The default domain need to be redirected to bosh interface i.e http://127.0.0.1:5290/http-bind. You can archive this by yunohost redirect app https://github.com/YunoHost-Apps/redirect_ynh#invisible-proxy-redirect.
It will be proxy pass with bosh.domain.tld/http-bind -> http://127.0.0.1:5290/http-bind.