Trouble trying to monitor Oracle database

I have access to two servers, production server and development server.

This is the error I get when trying to monitor development server

Unable to connect to Oracle Server.
Error Message:
Excepci�n Io: Connection refused(DESCRIPTION=(TMP=)(VSNNUM=153093120)(ERR=12505)(ERROR_STACK=(ERROR =(CODE=12505)(EMFI=4))))

I could successfully add the production server (My user doesn't have DBA privileges so I got refused with "table or view does not exist", but the point is, the connection to the server was made successfully)

TNSNAMES.ORA is

ZOOMDESA.EMPLOYER.COM.AR =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = zoomdesa)(PORT = 1533))
)
(CONNECT_DATA =
(SERVICE_NAME = ZOOMDESA)
)
)

I filled the fields as follows:

Host Name / IP Address: zoomdesa
do not resolve DNS name: Unchecked
subnet mask: 255.255.255.0
port: 1533
Polling interval: 5

username/password: user with dba privileges
Instance Name (Service Name): zoomdesa

I can log in with SQL*Plus correctly.

Since the error mesage says ERR=12505 I looked it up:

TNS-12505 TNS:listener could not resolve SID given in connect descriptor

Cause: The SID in CONNECT_DATA was not found in the listener's tables.

Action: Check to make sure that the SID specified is correct. The SIDs that are currently registered with the listener can be obtained by typing "LSNRCTL SERVICES listener_name". These SIDs correspond to SID_NAMEs in TNSNAMES.ORA, or DB_NAMES in the INIT.ORA file.