Unable to access internet - external proxy

[Roverius]

Hello,

I just installed a pfsense on a watchguard x700 box.
With the original wachtguard software i could connect to the internet without any problems.

So whats connected:
On WAN –> ip lease from external DHCP --> no problem
ON LAN --> used as trusted connection for configuration of the pfsense --> no problem
ON OPT1 --> connection(s) to workstations --> given ip from dhcp --> no problem

To connect the internet we use a external proxy server and i entered this information in "System - Advanced - Miscellaneous - Proxy URL"
The DNS server(s), also external, i entered in "System - DNS servers - + gateway = none"

I can test with DNS lookup if a ip adress resolves --> thats working

But still, i can't connect to the internet.

What do i wrong, or where should i place proxy/dns servers.

I added a rule, to test, on WAN, LAN, OPT1 with no restrictions.

Ping test from WAN = OK
Ping from LAN and OPT1 is 100% packet loss --> NOK

Thanks for any support on this.