The web interface is functioning.
XXX. XXX. XXX. XXX:8089/admin
Is that what you mean?
Or is this what is meant:
http://XXX.XXX.XXX.XXX:8089/admin/api.php outputs the following:
{
“error”:    {
“key”:    “bad_request”,
“message”:    “Bad request”,
“hint”:    “The API is hosted at pi.hole/api, not pi.hole/admin/api”
},
“took”:    3.6716461181640625e-05
}