For Detailed Process Watch Video::
Steps to solve the error
pgadmin 4 fatal error the application server could not be contacted
1 step :: go to control panal
2 step : click on program and fetures
3 step : click on postgreySQl
4 step::click on uninstall and change
5 step :: choose individual component
6 step :: choose pgadmin and click on next and wait until delete completed
7 step : download pgadmin::
https://www.postgresql.org/ftp/pgadmin/pgadmin4/v5.4/windows/
