The DB link is not connected

Both sides of the database, not in one place. are all Oracle.

Tried many times, sometimes prompting the connection to refuse, sometimes not connected. Later changed the Dblink creation script, as follows, only succeeded.

--Create Database link
Create DATABASE link XLINK
Connect to xx --the user name connected to the other database

Identified by xx--Password

Using ' (DESCRIPTION =
(Source_route = yes)
(ADDRESS = (PROTOCOL = TCP) (HOST = x.x.x.x) (PORT = 1521)) ----The IP of the other database, and the port
(ADDRESS = (PROTOCOL = TCP) (HOST = x.x.x.x) (PORT = 1521)) -----The IP and port of the local database
(Connect_data =
(service_name = ORCL) ---Local database name
)
)‘;

The DB link is not connected