SQL DEVELOPER IO ERROR: The network adapter could not establish the connection | SID error

go to this path on your computer where oracle is installled. F:\app\SVS\product\12.1.0\dbhome_1\NETWORK\ADMIN 1.check listener.ora and tnsnames.ora to verify portnumber and hostname 2.check whether lsnrctl is sleeping. if so, make it start. 3.if you are fine with above steps and even showing the errors. finally check your input for user and password is valid. select service name & type orcl and press connect button. successfully connected thanks for watching.