Unable to connect using SQLPLUS from the client to the server. Error raised as "Could not resolve the Connect Identifier specified"

Unable to connect using SQLPLUS from the client to the server. Error
raised as "Could not resolve the Connect Identifier specified"

I have 2 different servers. Both are having the Listener and TNSNAMES
files correctly configured, and the listener.ora and tnsnames.ora files
are also similar. And for example the service names are serv_name1 and
serv_name2. And the remote login parameters are also the same as shown
below:
SQL> show parameter remote;
remote_dependencies_mode string TIMESTAMP
remote_listener string
remote_login_passwordfile string EXCLUSIVE
remote_os_authent boolean FALSE
remote_os_roles boolean FALSE
result_cache_remote_expiration integer 0
The listener also is up and running. The Tnsping on both the servers with
their respective service names are pinging. I am able to connect to both
the servers using SQL Developer. And using SQLPLUS, I am able to connect
from a client system to server1 using serv_name1, but I'm unable to
connecto to server2 using serv_name2.