latest /usr/share/perl5/EBox/Network/Model/DNSResolver.pm cuases problem to squid3..
Can't locate object method 'authenticationMode' via package 'EBox::Squid'
Can't locate object method 'authenticationMode' via package 'EBox::Squid' at /usr/share/perl5/EBox/Network/Model/DNSResolver.pm line 154.
restored from a backup the specific file and http proxy works again!!
Waiting a new fix from zentyal