SQL & PL/SQL :: Linking Two Database

I am using two databases one prd1 and another ftn. I want to do some data verification between these two databases. So I created the following db link in prd1 and also in ftn.

CREATE PUBLIC database LINK ftn
CONNECT TO ftn_link IDENTIFIED BY password
USING ftn

CREATE PUBLIC database LINK prd1
CONNECT TO prd1_link IDENTIFIED BY password
USING prd1

I gave the following sql command from prd1 but it showed error message.

ORA-12154: TNS:could not resolve service name

SELECT A.CUST_ID_MSS_OWNER, B.CUST_ID_MSS_OWNER
FROM MSS_V_CAR_REC A, mss_v_car_rec@ftn b
WHERE a.lic_no_org = b.lic_no_org;

I have already created the sql net configuration also.