I had a problem today connecting to my Oracle express database from SQL Developer on Windows 10 with the error: The network adapter could not establish the connection.
Connection did work from SQL*PLUS (Run SQL Command line).
The OracleXETNSListener service was stopped in my services and restarting it did not work.
Turns out the problem was that I changed my computer name yesterday and the service does not use localhost, but the computername.
To solve this I changed the hostname in these files:
Stopped/started the database and everything's fine.
Saw these alternate solutions (did not test):
solution 1: Add the old hostname to C:\Windows\System32\drivers\etc\hosts
SQL> alter system set LOCAL_LISTENER='(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))' scope=both; SQL> alter system register;