pgAdmin 4 not opening

Dear sir/madam

i am completely new to postgreSQL and i am tring to install Dspace on my personal computer.but, when i try to open the pgAdmin after installing jdk and 10.0.2 and postgresql 4.1 even Apache tomcat 9it redirects me to my default browser(chrome) and shows me :

on the url but nothing else is displayed can you please tell me how to fix it or what did i do wrong?

regards

assay