Default Web browser not working despite wifi connection

Dear all,

I get regularly some problem of connection with the android web browser.
When I am connectd to wifi, some applications connect (what app, skype) but some others no (shazam, tuneIn).

In addition when I start the web browser, the load bar remains stuck at 10% and the screen displays "webpage not available".
Do you have any idea to solve this issue?

For information I am using a VPN but the issue happen also when I disconnect it !

Thanks for your help and advice.

my phone :
Samsung S3 GT- I9300
android version 4.1.2