Does anyone know what these errors mean?

[macMonkey]

Server side error 404: Controller 'Undefined' does not exist. espo-main.js:37287:20
    onError espo-main.js:37287

Uncaught (in promise)
XMLHttpRequest { errorIsHandled: false, readyState: 4, timeout: 60000, withCredentials: false, upload: XMLHttpRequestUpload, responseURL: "http://localhost/espocrm/api/v1/undefined", status: 404, statusText: "Not Found", responseType: "", response: "" }
​
errorIsHandled: false
​
mozAnon: false
​
mozSystem: false
​
onabort: null
​
onerror: function onerror()
​​
length: 0
​​
name: ""
​​
<prototype>: function ()
​
onload: function onload()
​
onloadend: null
​
onloadstart: null
​
onprogress: null
​
ontimeout: function ontimeout()
​
readyState: 4
​
response: ""
​
responseText: ""
​
responseType: ""
​
responseURL: "http://localhost/espocrm/api/v1/undefined"
​
responseXML: null
​
status: 404
​
statusText: "Not Found"
​
timeout: 60000
​
upload: XMLHttpRequestUpload { onloadstart: null, onprogress: null, onabort: null, … }
​
withCredentials: false
​
<prototype>: Object { … }

[yuri]

The second is timeout of waiting for server response. Could be internet offline or the server offline.

The first is unknown to me. Could be a customization issue.