Why cannot visit website when Charles app is closed?

Sorry, my English is poor, the following text if they are not fluent, but also look sorry

I downloaded a app, Its name is charles,Once when I forced it off,I found out when I open it,I can visit website,but when i close it again,Then i try to visit the website,I cannot visit.

Then I try to go to Internet search on a solution,I was required to reboot, or restart my computer,I even re-download the software,Still can not visite the website