After 4 hours continuous efforts, finally I got answer of my question. I am writing this for others facing the same problem. There are three things you have to take care to resolve this error.
First thing is to change your oracle database port number. You can find this in oracle folder location go to oracle folder and follow this hierarchy oracle -> product -> 11.2.0(you may have different folder name according to your version) -> server -> config
in config folder you will find log and script folders go to log folder and open postDBConnection.log file open it in text editor you will find
dbms_xdb.sethttpport('8080');
just change 8080 to any other port number do the same for script folder open postDBConnection.sql file and modify it. Your port number will be changed.
Second thing is you can check for your hostname and port number for listener. follow the folder hierarchy
oracle -> product -> 11.2.0(you may have different folder name according to your version) -> server -> network -> Admin now open listener.ora and tnsnames.ora open both files one by one and verify hostname and port number. This information should be same in both files as well as in you connection.
Third thing is be sure that your listener port is started. Right click on "ThisPC" you will find "Manage" option click on it now click on "Services and Aplicaions" now click on "Services" in services find oracle service. Here you will find "OracleXETNSListener" or another name of oracle listener. Right click on it and start it. Now restart your oracle database.
For further help refer to the link below:
https://www.youtube.com/watch?v=pMQXVihgrrE&t=254s
