Bitrix order exchange with 1C. How to fix the error "An error occurred on the server side. Unknown import status received. Server response: 0success"?

Question

1C

Hello!
We set up the unloading of goods from 1C to Bitrix in one node. Everything works great.
We set up an exchange of orders in another node. When I try to run it, I get this error:

Sending an authorization request.
Sending an initialization request to determine the data exchange version.
documents___4ca6ab53-eed1-4953-a468-03b3b6042e1c.xml: An error occurred on the server side. Unknown import status received.
Server response:
0success

Server response: 0success

The settings are the most standard: just unloading orders.
Tried disabling zip archiving.
Did a system and access check.

Tell me, please, what can be done? Where to dig?
Thanks in advance!