I can't download apps on my iPad2

See the Apple Support article(s) below.

Apps won’t downloaded.       

App Store, iTunes Store, or other Apple services - If you can't connect

Some things you can try. Do you have access to another WiFi network where you can try? That has worked for several people.

Try a restart.

Restart your iPhone, iPad, or iPod touch         

Try a forced restart.

Reset Device.