APEX

Domain name is an important parameter you need to have that handy before proceeding here:

1. Verify the domain name:

show parameters db_domain;

OR

SELECT value FROM v$parameter WHERE UPPER(name) = 'DB_DOMAIN';

2. Change if applicable (Take DBA help)

If the domain name has any characters other than A-Z (letters), 0-9 (numerals), _ (underscore), # (hash), $ (dollar),. (period), or @ (at the rate), for example, a '-' (hyphen), then change the domain name.

alter system set db_domain='<domain_name_with_illegal_char_replaced_with_legal_char>' scope=spfile sid='*';

3. Have the connection string in following format.

    SERVER=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort))(CONNECT_DATA=(SERVICE_NAME=MyOracleSID)))

4. Provide the target database name:

    SELECT value FROM v$parameter WHERE UPPER(name) = 'DB_NAME';

Then you can have all these to check your connection.

Please mark Helpful or Correct if this information helped you in any way.

Cheers !