How to catch the reason for not working address autocomplete?

Question

1C-Bitrix

Greetings.
Moved the site to a test server. Everything works, except for the address autocomplete when placing an order.
I am attaching two screenshots from the test and working servers:
Test (autocomplete does not work)
Worker (autocomplete works)

In the developer console in chrome, it is not visible where the call is going. In test mode, outputs NULL when entering a street address. On the working server displays answers.

10: {id: "8CAD81A1-0E97-4801-8F24-56C7B56FECC0", name: "Тверская пл", zipCode: "125009"}
11: {id: "0ECDE158-A58F-43AF-9707-AA6DD3484B56", name: "Тверская ул", zipCode: ""}
12: {id: "3F28B35F-CAAB-4715-94CD-9F652A441690", name: "Тверская Застава пл", zipCode: "125047"}
13: {id: "94D0CF51-2820-4409-BBD7-4A7D36F2922B", name: "Тверская-Ямская 1-я ул", zipCode: ""}
14: {id: "5BA0C536-B105-4C8B-8B9A-8B06A64A4073", name: "Тверская-Ямская 2-Я ул", zipCode: "125047"}
15: {id: "1735120D-E814-4CA2-BF8D-5F53B42EA541", name: "Тверская-Ямская 3-Я ул", zipCode: "125047"}
16: {id: "1B366B75-A6BB-4037-B5AB-FF8092DC3405", name: "Тверская-Ямская 4-Я ул", zipCode: "125047"}
17: {id: "016862F5-F905-46B3-84D3-69539A402C90", name: "Тверской проезд", zipCode: "123104"}
18: {id: "2604E353-B9DD-4542-A8BF-020C8F982797", name: "Тверской б-р", zipCode: ""}
19: {id: "4F790518-2284-459F-8C69-DA6EEBB2E4DC", name: "Тверской-Ямской 1-й пер", zipCode: "125047"}
20: {id: "0EAAC3C2-F7D6-42C4-ABB5-635A8CA26372", name: "Тверской-Ямской 2-й пер", zipCode: "125047"}

I found out in the site files that the kladr is loaded with a self-written script, but I'm not a programmer.
The site was written and corresponded at one time by different developers, whom I actually don’t know and can’t be found anymore.
There is nothing in the webserver logs regarding autocomplete, even in debug mode.
Tell me where to dig?

Answer 1

Where autocomplete is knocking. Most likely there the path was hard-coded instead of relative.

Answer 2

Hypothesis : to autocomplete addresses, the dadata service is used, so that requests from your server are accepted by the dadata service, a hash associated with your domain is added to it, so that no one would use the computing power of the service for free. And after moving to the test server, your domain has changed and, accordingly, dadata ignores all your requests and therefore no hints appear.