Ws disconnection when running inside docker network

Dear community,

I am experiencing an issue with the library. Below mi config:
- docker compose running:
-- mosquitto service with name mqtt-broler and exposing 1883 and 9001 for mqtt and was respectively.
-- http application with paho client library for ws.

Both are connected at the same time to an internal docker network.
I am able to ping each container from the other by its name.

Problem:
If I connect to the broker using ws://localhost:9001/mqtt works perfectly.
If I connect to the broker using ws://mqtt-broler:9001/mqtt I get a disconnection message. It never connects.

Just for curiosity I tried with mqtt instead of ws and worked perfectly.

Could someone help me with that?

Regards