WFS Container is not able to connect to 3DCityDB Container

[Itsman-AT]

Hello,
I tried to set up the 3DCityDB and WFS Docker container and the WFS container does not seem to be able to connect to the PostgreSQL of the 3DCityDB container. I checked the port, DB name and user name and password and it seems all correct. I also tried to connect via Navicat and I can see the citydb DB. This is the error I get:

[localhost-startStop-1] org.apache.tomcat.jdbc.pool.DataSourceProxy.getPool Error during connection pool creation. org.postgresql.util.PSQLException: Connection to localhost:5435 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

Any ideas`? Is there a need to adjust pg_hba.conf maybe? I do not know, though, how to do this within the 3DCityDB container. Thanks in advance.