admin-ajax.php 404 (Not Found)

My site takes 30 seconds to load when going to the main page. Other pages are doing the same. Here are some details:

POST https://webiste/wp-admin/admin-ajax.php 404 (Not Found), this is the error I get when using DevTools; sometimes I ever get a 503 error.
Here is the text from the window that pops up when I click on the error:
r.onload = o(),
a = r.onerror = r.ontimeout = o("error"),
void 0 !== r.onabort ? r.onabort = a : r.onreadystatechange = function() {
4 === r.readyState && C.setTimeout(function() {
o && a()
})
}
,
o = o("abort");
try {
r.send(i.hasContent && i.data || null) "It stops here"
} catch (e) {
if (o)
throw e
}
},
abort: function() {
o && o()
}
}

How do I proceed to fix this?

• This topic was modified 1 year, 9 months ago by Jose Castaneda. Reason: fixed code block