Exactly, look at HTTP status code. 401 means Unauthorized, you need to supply valid username and password to be able to use RPC interface for that node.
The funny thing is that I don't know where to get them from.(
IP I took from the seeds
In curl, I specify any login and password, but I don’t know where to get which one is needed (
Why should you have the username/password if the node is not yours? Anyone can start a node, and can restrict the json API interface.